My next time I have to disturb the things, I'd go for a set. Last time I tried to buy viton orings, I had to take a stab in the dark at the proper viton composition with all the choices available, and I guessed wrong. The ones I got were too hard and it was a miracle I didn't split the caps getting them on, I had to beat the snot out of them to do it. I fully expected to have to buy another kit, but I had to take them off not too many miles later for unrelated reasons and they didn't fare as well coming off( total destruction) that ended my viton experiment for a while. So a properly matched viton set will be a welcomed sight.