Bought to replace my 10-year-old (!!!) stock rubber grips on my TREK Bruiser.
Instructions say to wet the inside of the sponges before slipping them on. Sure enough they got on without any trouble, popped in the end caps. Tested them the next day after they'd dried. They're on tight, I cannot move them at all.
They're also pretty comfortable.
I have a twist-style shifter mounted on the handlebar, so I had to fit one of the grips by cutting off a bit of one of the ends. No problem.