It's an E12 (exenal torx)socket, but it's threaded3/8'"-16 so replacements are readily available. I believe its' got an UHL length of 1-3/4" inches.
I've replaced them with studs, 3/8-6 by about two inches Then, intstall nunts and washers on the flying ends to retain.
Failing that, remove the OEMR bolts and replace with hex head or socket head capcrewx - both will work. Given that I have a clutch, I prefer the studs fo alignment..
5-90