GYTR rear fender rack

Dont know if this is the right spot, I have the GYTR rear rack and one of the big bolts fell out, does any one know the size of these, the head says 8.8 I need to know the length and millimeter, this will save me taking the muffler off and taking the other bolt out to match the size, Im lazy I guess, funny thing is I live in Canada and we are supposed to be metric, and everyone up here sell`s standard size. I may have to get one from another place on line, duh.