Just a sec I'll check. Found some. 1/4" The one from home depot is # D1420 Maybe that means 1/4-20 nut I don't know. First pic. I don't have the bolt I got with them. The nut is bonded into the rubber. I also have a couple of other ones that came off the car somewhere but I can't remember where. The three other pics. The bolt is 1/4" thread and the shoulder is 9/32"
