im sure that everybody has a tip to put the o ring on a senko but the other day i think on ebay there was somebody selling a aluminum tool to do this for like $15 which is dumb..anyway my tip is take a tube of caulking or silicone and cut the tip off the base make sure that the tip is big enough.. slide the senko in and roll the o ring down it will fall right in the middle...justa little tip 4 ya