Longines HydroConquest

Most Longines HydroConquest references take a 21 mm watch strap: 98 of 186. The lug width follows the case size: 32 mm case → 16 mm, 39 mm case → 19 mm, 41 mm case → 21 mm and 43 mm case → 21 mm.

Shop 16 mm Shop 19 mm Shop 20 mm Shop 21 mm Shop 22 mm

Longines HydroConquest lug width by case size

186 references measured. Updated 2026-10-29.

Case	Lug width	References	Watch strap attachment	For example
30 mm	15 mm	2	—	L3.284.4.56.6, L3.284.4.96.6
32 mm	16 mm	5	—	L3.370.3.87.6, L3.370.3.89.6, L3.370.4.56.6
39 mm	19 mm · 20 mm on 9 · 22 mm on 1	39	—	L3.647.3.16.7, L3.647.3.36.7, L3.647.3.56.7
41 mm	21 mm · 20 mm on 23 · 22 mm on 3 · 19 mm on 1	105	—	L3.643.4.56.6, L3.643.4.96.6, L3.649.4.16.6
43 mm	21 mm · 22 mm on 5 · 20 mm on 1	26	—	L3.782.3.06.7, L3.782.3.06.9, L3.782.3.56.7
44 mm	22 mm	4	—	L3.840.4.56.6, L3.840.4.96.6, L3.841.4.56.6
48 mm	24 mm · 20 mm on 2	5	—	L3.843.4.56.2, L3.843.4.56.6, L3.843.4.96.6

References that take a different watch strap

L3.640.3.56.7: 20 mm, not the 19 mm of most 39 mm cases
L3.640.3.96.7: 20 mm, not the 19 mm of most 39 mm cases
L3.640.4.06.6: 20 mm, not the 19 mm of most 39 mm cases
L3.640.4.56.6: 20 mm, not the 19 mm of most 39 mm cases
L3.640.4.96.6: 22 mm, not the 19 mm of most 39 mm cases
L3.641.4.56.6: 20 mm, not the 19 mm of most 39 mm cases
L3.641.4.96.6: 20 mm, not the 19 mm of most 39 mm cases
L3.688.4.19.6: 20 mm, not the 19 mm of most 39 mm cases
L3.688.4.59.6: 20 mm, not the 19 mm of most 39 mm cases
L3.740.3.96.7: 20 mm, not the 19 mm of most 39 mm cases
L3.642.4.56.6: 20 mm, not the 21 mm of most 41 mm cases
L3.642.4.96.6: 20 mm, not the 21 mm of most 41 mm cases
L3.644.4.56.2: 20 mm, not the 21 mm of most 41 mm cases
L3.644.4.56.6: 20 mm, not the 21 mm of most 41 mm cases
L3.644.4.96.2: 20 mm, not the 21 mm of most 41 mm cases
L3.644.4.96.6: 22 mm, not the 21 mm of most 41 mm cases
L3.671.4.76.6: 20 mm, not the 21 mm of most 41 mm cases
L3.673.4.76.2: 22 mm, not the 21 mm of most 41 mm cases
L3.673.4.76.6: 20 mm, not the 21 mm of most 41 mm cases
L3.689.4.03.6: 20 mm, not the 21 mm of most 41 mm cases
L3.689.4.53.2: 20 mm, not the 21 mm of most 41 mm cases
L3.689.4.53.6: 20 mm, not the 21 mm of most 41 mm cases
L3.689.4.59.2: 20 mm, not the 21 mm of most 41 mm cases
L3.689.4.59.6: 20 mm, not the 21 mm of most 41 mm cases

And 21 more in the full list below.

Questions about the Longines HydroConquest

Do all Longines HydroConquest case sizes take the same watch strap?

No. The lug width changes with the case size: the 32 mm case takes 16 mm, the 39 mm case takes 19 mm, the 41 mm case takes 21 mm, the 43 mm case takes 21 mm and the 48 mm case takes 24 mm. Check your case diameter before you buy.

Can two Longines HydroConquest watches with a 41 mm case take different watch straps?

Yes. Of the 105 Longines HydroConquest references with a 41 mm case, 78 take 21 mm, 23 take 20 mm and 3 take 22 mm. The reference number decides, not the case size alone.