This is a correctly-domed plexiglass armoured with a tension ring, for Breitling Ref. 765 AVI & CP chronographs produced from 1953 to 1967. It is THE plexi glass you should use if you want your watch to have a perfectly fitting plexi and the correct look. It is the only plexi glass in the market that will CORRECTLY fit the Ref. 765 AVI & CP produced from 1953 to 1967, which takes a specific type of plexi glass. This is not a Breitling-branded product. The listed price is for one plexi glass. Plexis for other vintage Breitling chronographs are listed separately. Apologies for the mediocre photos but it is very difficult to photograph a plexiglass!
Feel free to contact me for whatever questions you might have and remember that I do not accept returns for such parts.