My Franke Eiger mixer tap started leaking from where the spout joins the body. I took the spout off, the o rings looked ok so I put a bit of silicone grease on and put it back. After a couple of days it started again. I have a friend that has about six different boxes of o rings, he must have about 1000 in all so I thought I would get one easily. Not one was the exact size, they were all slightly too thick but I got one that was very close. Well obviously not close enough as the spout wouldn’t push back in to the body. I know I can get two o rings a grub screw and an Allen key for about £6 on Amazon or e bay but it seems a lot to pay when I only actually need one o ring. I don’t think my local plumbers merchant would be too chuffed if I went in and asked them to match one o ring. Does anybody have any ideas because if I buy any of the random sets of 50 to 200 rings I think they will probably all be slightly too thick like my friend’s.