These are the correct domed acrylic plexiglasses for your Omega Speedmaster chronograph watches; both the smaller automatic (39mm cases like the Ref. 3510.5000, 175.0032, 175.0033 etc.) and larger manual-wind moonwatch models (42mm case like the Ref. 145.022, 357.5000, etc). They both have a black armoured ring. They do not have the Omega logo in the centre. For the smaller automatic speedmaster, the diameter is Ø31.20mm and for the larger manual-wind moonwatch the diameter is Ø34.10mm. They are THE acrylic glasses you should use if you want your watch to have a perfectly fitting plexiglass and the correct overall look. It is the only plexiglass in the market that will CORRECTLY fit these watches (other than the original ones of course which are unfortunately now restricted by Omega), which take a specific type of plexiglass. In my photos you can see examples of how they will look, on watches which we serviced in our store here at Localtime. The listed price is for one unit and does not, of course, include any watch you see in this listing, which is shown for presentation purposes only.
Please note that I do not accept returns for parts and feel free to contact me for whatever questions you might have.