Unitas 6303 – interchangeable spare parts

Unitas (UT) 6303 movement

Which spare parts fit the Unitas 6303 movement? For every part you can see which other calibers use the same part according to the original interchangeability list.

31Parts with interchange data

62Calibers sharing parts

Note: We have compiled this overview to the best of our knowledge and belief, based on the original interchangeability lists of Unitas (UT) and the original spare-part labels. All information has been carefully checked but is provided without guarantee. Please verify the interchangeability yourself before fitting, especially the height, diameter and execution of the part.

🔧 Interchangeable parts

Part no.	Description	Also fits
182ISO 20.030	Barrel and cover	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6320
195ISO 20.060	Barrel arbor	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
206ISO 30.015	Center wheel	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Height 406 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N
210ISO 30.025	Third wheel	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
227ISO 30.027	Sweep second wheel	Unitas 6300 Unitas 6300N Height 615 Unitas 6300 Unitas 6300N Height 640 Unitas 6300 Unitas 6300N Height 690 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N
245ISO 31.080	Cannon pinion with clam notch	Unitas 6300 Unitas 6300N Height 224 Unitas 6300 Unitas 6300N Height 249 Unitas 6300 Unitas 6300N Height 299 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N
255ISO 31.046	Hour wheel	Unitas 6300 Unitas 6300N Height 125 Unitas 6300 Unitas 6300N Height 150 Unitas 6300 Unitas 6300N Height 200 Unitas 6300 Unitas 6300N
260ISO 31.041	Minute wheel	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
301ISO 40.301	Regulator for flat hairspring	Unitas 6300 Unitas 6305
307ISO 40.301	Regulator with adjustable stud holder, for flat hairspring	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
311ISO 70.800	Upper cap jewel with end-piece	Unitas 176 Unitas 376 Unitas 600 Unitas 620 Unitas 6300 Unitas 6305 Unitas 6310 Unitas 6311 Unitas 6312 Unitas 6320 Unitas 6330 Unitas 6410 Unitas 6411 Unitas 6412 Unitas 6415
330ISO 70.801	Lower cap jewel with end-piece	1st execution Unitas 200N Unitas 201N Unitas 376 Unitas 560 Unitas 570 Unitas 580 Unitas 600 Unitas 620 Unitas 630 Unitas 640 Unitas 650 Unitas 6300 Unitas 6305 Unitas 6310 Unitas 6320 Unitas 6330 Unitas 6340 Unitas 6342 Unitas 6343 Unitas 6410 Unitas 6411 Unitas 6412 Unitas 6415 Unitas 6450 Unitas 6452 Unitas 6460 2nd execution Unitas 376 Unitas 6300 Unitas 6305 Unitas 6310 Unitas 6311 Unitas 6312 Unitas 6340 Unitas 6342 Unitas 6343 Unitas 6410 Unitas 6411 Unitas 6412 Unitas 6415 Unitas 6450 Unitas 6452 Unitas 6460
336ISO 70.806	Upper cap-jewel with end-piece, for escape wheel	2nd execution Unitas 176 Unitas 199 Unitas 287 Unitas 376 Unitas 600 Unitas 640 Unitas 650 Unitas 6300 Unitas 6305 Unitas 6310 Unitas 6311 Unitas 6312 Unitas 6320 Unitas 6340 Unitas 6342 Unitas 6343 Unitas 6410 Unitas 6411 Unitas 6412 Unitas 6415 Unitas 6450 Unitas 6452 Unitas 6460
346ISO 70.807	Lower cap jewel with end-piece, f. esc. wheel	1st execution Unitas 376 Unitas 444 Unitas 497 Unitas 498 Unitas 560 Unitas 570 Unitas 580 Unitas 600 Unitas 620 Unitas 640 Unitas 650 Unitas 6300 Unitas 6305 Unitas 6310 Unitas 6311 Unitas 6312 Unitas 6340 Unitas 6342 Unitas 6343 Unitas 6410 Unitas 6411 Unitas 6412 Unitas 6415 Unitas 6450 Unitas 6452 Unitas 6460 Unitas 6500 2nd execution Unitas 6300 Unitas 6305 Unitas 6310 Unitas 6311 Unitas 6312 Unitas 6340 Unitas 6342 Unitas 6343 Unitas 6410 Unitas 6411 Unitas 6412 Unitas 6415 Unitas 6450 Unitas 6452 Unitas 6460
401ISO 51.010	Winding stem	Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
407ISO 31.121	Clutch wheel	Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
410ISO 31.120	Winding pinion	Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
415ISO 31.020	Ratchet wheel	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
420ISO 31.023	Crown wheel	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
422ISO 81.067	Crown wheel ring	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
425ISO 51.120	Click	2nd execution Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
430ISO 61.080	Click spring	Unitas 176 2e Unitas 376 Unitas 600 Unitas 620 Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6310 Unitas 6310N Unitas 6311 Unitas 6311N Unitas 6312 Unitas 6312N Unitas 6325 Unitas 6326 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6410 Unitas 6410N Unitas 6411 Unitas 6411N Unitas 6412 Unitas 6412N Unitas 6415 Unitas 6415N Unitas 6425 Unitas 6426 Unitas 6427 Unitas 6428 Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
435ISO 51.050	Yoke	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6310 Unitas 6310N Unitas 6311 Unitas 6311N Unitas 6312 Unitas 6312N Unitas 6325 Unitas 6326 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6410 Unitas 6410N Unitas 6411 Unitas 6411N Unitas 6412 Unitas 6412N Unitas 6415 Unitas 6415N Unitas 6425 Unitas 6426 Unitas 6427 Unitas 6428 Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
440ISO 61.100	Yoke spring	Unitas 176 Unitas 376 Unitas 600 Unitas 620 Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6310 Unitas 6310N Unitas 6311 Unitas 6311N Unitas 6312 Unitas 6312N Unitas 6320 Unitas 6325 Unitas 6326 Unitas 6330 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6410 Unitas 6410N Unitas 6411 Unitas 6411N Unitas 6412 Unitas 6412N Unitas 6415 Unitas 6415N Unitas 6425 Unitas 6426 Unitas 6427 Unitas 6428 Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
443ISO 51.080	Setting lever	Unitas 176 Unitas 376 Unitas 600 Unitas 620 Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6310 Unitas 6310N Unitas 6311 Unitas 6311N Unitas 6312 Unitas 6312N Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6410 Unitas 6410N Unitas 6411 Unitas 6411N Unitas 6412 Unitas 6412N Unitas 6415 Unitas 6415N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
443/5443ISO 51.080.06/.01	Setting lever	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
445ISO 51.090	Setting lever spring	Unitas 176 Unitas 376 Unitas 600 Unitas 620 Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6310 Unitas 6310N Unitas 6311 Unitas 6311N Unitas 6312 Unitas 6312N Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6410 Unitas 6410N Unitas 6411 Unitas 6411N Unitas 6412 Unitas 6412N Unitas 6415 Unitas 6415N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N according to original label Unitas 175 Unitas 176 Unitas 177 Unitas 228 Unitas 376 Unitas 500 Unitas 600 Unitas 610 Unitas 620 Unitas 640 Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6310 Unitas 6310N Unitas 6312 Unitas 6312N Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6410 Unitas 6410N Unitas 6411 Unitas 6412 Unitas 6412N Unitas 6415 Unitas 6415N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
450ISO 31.100	Setting wheel	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N 2nd execution Unitas 650 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N Height 50 Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N Unitas 6450 Unitas 6450N Unitas 6452 Unitas 6452N Unitas 6460 Unitas 6460N
702ISO 30.040.12	Escape wheel and pinion, pivoted, for two end-pieces	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
705ISO 30.040	Escape wheel and pinion	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308
710ISO 40.010	Jewelled pallet fork and stat	Unitas 6300 Unitas 6300N Unitas 6305 Unitas 6305N Unitas 6308 Unitas 6340 Unitas 6340N Unitas 6342 Unitas 6342N Unitas 6343 Unitas 6343N

Source: original interchangeability lists of Unitas (UT) (checked transcription) and checked original spare-part labels · as of 2026-10-28. Height / execution: the part fits only in this height or execution.

🌀 Matching mainspring

Mainspring dimensions for Unitas 6303 (height × diameter × thickness × length) and matching mainspring in our shop:

Unitas 6300 à 6303: 1.50 × 11.5 × 0.14 × 360 mm (GR 4229-1)

🔗 Movements sharing the most parts

→ All calibers of Unitas (UT)

❓ Frequently asked questions

Which Unitas 6303 spare parts also fit other movements?

For the Unitas 6303, 31 part numbers are listed as interchangeable. Together they fit 62 other calibers – the table below shows which part fits which movement.

Which movements share the most parts with the Unitas 6303?

The most shared parts: Unitas 6300 (46 parts), Unitas 6300N (39 parts), Unitas 6305 (36 parts).

Which mainspring fits the Unitas 6303?

According to the Générale Ressorts catalogue (height × diameter × thickness × length): 1.50 × 11.5 × 0.14 × 360 mm (GR 4229-1, hand-wound, special version (1)).