Just bought an O-RING Assortment 420 pieces . 3.55 mm by 1.8mm to 50 mm by 3.55mm  $12.99.top value

round ones scotty

It does not mention composition it says tested according DIN 3771-1 ISO 188. they are packed in a case similar to the type I've bought from the Servo .

good luck with it chaps.........i'll continue to find mine at work

You blokes can be fucking ANAL. I've got my Mercruiser rams to rebuild and a dozen taps around the house if these o rings are the right size and they aren't the right composition I'll have the size . I don't have to go up to AUTO ONE and try 5 different rings I GOT THE SIZE . but you fucking get 'em from work

I shouldn't type under the influence.

I have one of these sets that my wife bought a few years ago. At the time I thought "why?" but they saved my bacon when I needed a 1 1/4" gasket for a through hull fitting on my boat to seal a parallel thread.