I donÔÇÖt think you want the buna material, lower temp resistance.

M2.5x90 Viton O-Ring, 75A Durometer, Round, Black, Viton, 90 mm ID, 95 mm OD, 2.5 mm Width (Pack of 5) https://www.amazon.com/dp/B00NJPP6KM/ref=cm_sw_r_cp_apip_Oc64WrB65mR2Q