""BUNA O-Ring, Size 2-209." If you can not locate o-rings at a plumbing store then your local hardware store, Lowes, Home Depot, ACE, OSH sell them in one-packs from Danco # 95. (The size is 15/16 X 11/16 x 1/8)."
It uses a plastic or reinforced rubber strap to go around the cylindrical object and is the least damaging tool to use for this application. Usually available in auto parts store. I carry one with me on all trips. Handel has been shortened for eae of use and packing.