Omega Spring Bars Size Guide
Last Update : October, 2026
We have created this reference chart for vintage and modern Omega watches, including model names, reference numbers, and the corresponding spring bar sizes.
All information in this chart is based on our own research and collected data. While we strive to provide the most accurate and up-to-date information possible, 100% accuracy cannot be guaranteed, as spring bar specifications may vary depending on the watch model and application. We will continue reviewing and updating this chart as new information becomes available.
Omega watches commonly use spring bars with either a 1.5 mm or 1.8 mm diameter, depending on the watch and the type of strap or bracelet being fitted. Stainless steel bracelets typically require specific spring bar specifications, while leather straps may be fitted with thinner spring bars, depending on the model and application. Many collectors prefer 1.5 mm spring bars for leather straps.
At Milano Straps, we offer both 1.5 mm and 1.8 mm spring bars to help you find the right option for your watch and strap combination.
Use the chart below as your guide, select the appropriate spring bar size, and shop our Omega spring bars in 1.5 mm or 1.8 mm.
Shop Omega 1.8mm Spring Bars - Click Here
Shop Omega 1.5mm Spring Bars - Click Here
Modern Omega Reference Specifications (2006–2026)
| Collection / Model | Reference | Lug Width (Strap Size) | Bracelet Spring Bar (OEM) | Leather/Rubber Spring Bar (OEM) | Pivot Tip Diameter |
|---|---|---|---|---|---|
| Speedmaster Moonwatch Pro (Cal. 3861) | 310.30.42.50.01.001 / 002 | 20 mm | 19 mm | 20 mm | 0.90 mm |
| Speedmaster Moonwatch Pro (Cal. 1861) | 311.30.42.30.01.005 / 006 | 20 mm | 19 mm | 20 mm | 0.90 mm |
| Speedmaster "Ed White" Cal. 321 | 311.30.40.30.01.001 | 19 mm | 19 mm | 19 mm | 0.90 mm |
| Speedmaster '57 (40.5mm) | 332.10.41.51.01.001 | 20 mm | 19 mm / 20 mm | 20 mm | 0.90 mm |
| Speedmaster Dark Side of the Moon (44.25mm) | 311.92.44.51.01.003 / 007 | 21 mm | N/A (Strap only) | 21 mm | 0.90 mm |
| Speedmaster Racing Co-Axial (44.25mm) | 329.30.44.51.01.001 | 21 mm | 21 mm | 21 mm | 0.90 mm |
| Seamaster Diver 300M Co-Axial (42mm) | 210.30.42.20.01.001 | 20 mm | 19 mm (068ST2207) | 20 mm | 0.90 mm |
| Seamaster Diver 300M "NTTD" 007 | 210.90.42.20.01.001 | 20 mm | 20 mm (Titanium mesh) | 20 mm (NATO) | 0.90 mm |
| Seamaster Diver 300M Ceramic (41mm) | 212.30.41.20.01.003 | 20 mm | 19 mm / 20 mm | 20 mm | 0.90 mm |
| Seamaster Planet Ocean 600M (43.5mm) | 215.30.44.21.01.001 | 21 mm | 21 mm | 21 mm | 0.90 mm |
| Seamaster Planet Ocean 600M (39.5mm) | 215.30.40.20.01.001 | 19 mm | 19 mm | 19 mm | 0.90 mm |
| Seamaster Planet Ocean 600M (42mm) | 2201.50.00 / 232.30.42.21.01.001 | 20 mm | 20 mm | 20 mm | 0.90 mm |
| Seamaster Planet Ocean 600M (45.5mm) | 232.30.46.21.01.001 | 22 mm | 22 mm | 22 mm | 0.90 mm |
| Seamaster Aqua Terra 150M (41mm) | 220.10.41.21.01.001 | 20 mm | 20 mm | 20 mm | 0.90 mm |
| Seamaster Aqua Terra 150M (38mm) | 220.10.38.20.01.001 | 19 mm | 19 mm | 19 mm | 0.90 mm |
| Seamaster 300 Heritage (41mm) | 234.30.41.21.01.001 | 21 mm | 21 mm | 21 mm | 0.90 mm |
| Seamaster Planet Ocean Ultra Deep | 215.30.46.21.03.001 | 22 mm | 22 mm (HD 2.0mm) | 22 mm (HD 2.0mm) | 1.00 mm |
| Seamaster Railmaster (40mm) | 220.10.40.20.01.001 | 20 mm | 20 mm | 20 mm | 0.90 mm |
| Globemaster Co-Axial (39mm) | 130.30.39.21.03.001 | 20 mm | 20 mm | 20 mm | 0.90 mm |
| De Ville Prestige (40mm & 39.5mm) | 434.13.40.20.02.001 / 424.13.40 | 19 mm | 19 mm | 19 mm | 0.90 mm |
Vintage Omega Reference Specifications
| Era / Collection | Reference(s) | Lug Width | Bar Body Diameter | Pivot Tip Diameter | Note |
|---|---|---|---|---|---|
| Pre-Moon Speedmaster | CK 2915, CK 2998, 105.002, 105.003 | 19 mm | 1.50 - 1.80mm | 0.85 mm | Straight lug cases |
| Speedmaster Professional | 105.012, 145.012, 145.022 | 20 mm | 1.50–1.80 mm | 0.85 mm | Twisted lyre lugs |
| Vintage Seamaster 300 | 165.024, 166.024 | 20 mm | 1.80 mm | 0.85 mm | Dive case |
| Early Seamaster 300 | CK 2913, 14755, 165.014 | 19 mm | 1.50–1.80 mm | 0.85 mm | Straight lug dive cases |
| Seamaster PloProf 600m | 166.077 | 24 mm | 1.80–2.00 mm | 0.85 mm | Heavy monobloc case |
| Vintage Seamaster Dress | 14761, 166.010, 166.022 | 18 mm | 1.50 mm | 0.85 mm | Thin profile dress lugs |
| Constellation "Pie-Pan" | 14381, 14900, 168.005 | 18 mm | 1.50 mm | 0.85 mm | Dog-leg & lyre lugs |
| Constellation "C-Shape" | 168.017, 168.019, 168.029 | 19 mm | 1.50 mm | 0.85 mm | Genta case design |
| Flightmaster | 145.013, 145.026, 145.036 | 22 mm | 1.80 mm | 0.85 mm | Pilot helmet case |
| Speedmaster Mark II | 145.014 | 20 mm | 1.80 mm | 0.85 mm | Integrated barrel case |
| Speedmaster Mark III / IV | 176.002, 176.009 | 22 mm | 1.80 mm | 0.85 mm | Heavy pilot case |
| Geneve Automatic | 166.041, 166.070, 166.0163 | 18 mm | 1.50 mm | 0.85 mm | Entry vintage casing |
Production Hardware Tolerances
Lug Hole Sizing
Modern cases (post-2006): Factory drilled at 0.95 mm – 1.00 mm; pair with 0.90-0.85 mm pivot pins.
Vintage cases (pre-1985): Drilled at 0.85 mm – 0.90 mm; pair with 0.90 mm – 0.85 mm pivot pins.
Leather Clearance Factor
For custom leather craft, building with 1.50 mm double-flanged bars ensures sufficient clearance against sharp case cutouts (especially on Cal. 3861 Moonwatch cases) without pinching or abrading the leather fold.
