What it is
The Sellita SW500 is the modern alternative to the Valjoux 7750. Sellita built it as part of the same strategy that produced the SW200-1 alternative to the ETA 2824-2: when ETA restricted external supply through the 2000s-2010s, Sellita developed parts-compatible alternatives so the rest of the industry could keep making watches without dependency on Swatch Group. The SW500 launched around 2010 and is now the de-facto modern Swiss automatic chronograph base for any brand outside the Swatch Group umbrella.
How it differs from the Valjoux 7750
Three details. Slightly higher power reserve: SW500 is rated at 58 hours vs the original 7750's 44 hours, achieved through a redesigned mainspring barrel. 27 jewels in some grades: SW500 adds 2 jewels over the 7750's 25, on the automatic-winding bridge. Modern silicon hairspring options: top-tier SW500 grades offer silicon hairsprings; the 7750 is Nivarox-only at most price points. Otherwise: same 30 mm diameter, same 7.9 mm thickness, same cam-actuated chronograph, same oscillating pinion, same 6-9-12 day-date layout, same Côtes de Genève / perlage finishing options. A watchmaker who can service a 7750 can service an SW500 with no retraining.
Sellita supply pragmatics
Where the 7750 has factory restrictions (only ETA-contract brands can buy it), the SW500 is sold to anyone with a purchase order. This is the entire reason it exists. By 2026 the SW500 is in:
Breitling entry-tier chronographs (some refs), Oris Big Crown ProPilot Chrono, Bremont chronographs (some refs), Christopher Ward C65 / C8 chronos, Bell & Ross BR-03 chronograph, Sinn 144 St (some current refs), Hamilton Khaki Aviation chronograph (some refs), Damasko DC chronos, plus a long tail of microbrands. If a CHF 1,500-4,000 Swiss-made automatic chronograph launched after 2015 is not in-house and not Breitling B01-based, statistically it is an SW500.
Grading and brand-modified versions
Sellita grades the SW500 the same way as the SW200: Standard, Special, Premium, Top, with Top-grade including Glucydur balance, blued screws, Geneva stripes finishing, and tighter regulation. Brand-modified versions: Bremont BC-CAL.502 (Sellita SW500 base in some Bremont chronographs), Oris Cal. 752 (SW500 with Oris-specific decoration in the Big Crown ProPilot), Christopher Ward Cal. 753 (SW500 base in C65 chrono). The base architecture is identical; differences are in finishing, regulation, and rotor decoration.
Watches it powers
Oris Big Crown ProPilot Chrono, Breitling entry chronographs (some refs not running B01), Bremont MB Chronograph (some refs), Christopher Ward C65 Trident Pro Chronograph, Bell & Ross BR-03 Chrono, Sinn 144 St, Damasko DC56 / DC66, plus microbrand chronographs from Halios, Lorier, Magrette, and many others. By 2026 the SW500 is the most-used independent Swiss chronograph base.
Service notes
Service for an SW500-equipped watch runs CHF 350-550 at an independent watchmaker, CHF 700-1,100 at the brand. Parts (mainspring, oscillating pinion, automatic winding wheel) are universally available through Sellita's distribution and through cross-compatibility with Valjoux 7750 parts where applicable. Service interval: 5-7 years for daily wear. The cam-actuated chronograph requires periodic re-greasing of the lever pivots; this is routine watchmaking. Like the 7750, the SW500 has a steel hairspring in standard grades; demagnetisation may be needed periodically.
