I seem to remember buying only good quality ones for my Mararathon the ebay ones may not fit the bill.
Heres what you want.
https://www.guruwatches.co.uk/produc...ss-spring-bars
Made with quality 316L stainless steel in Switzerland to ensure your watch’s strap stays perfectly secure.
Designed for watches with pierced/drilled lug holes, such as Marathon’s Military watches.
Corrosion resistant, high strength, and easy to install.
Available in 18mm, 20mm and 22mm lug sizes.
Swiss Made Quality
NOTE: Do not use on the wrist watches that do not have drilled lugs