Easton EA50 Stem - Bolt sizes?

[vaulter1]

I'm having a hell of a time figuring out what size bolts are in an Easton EA50 Stem.  I actually have the stem but cannot figure out how to measure the bolts properly - I know it's the diameter but my tape measure's a bit worn and I don't want to buy the wrong replacement bolts.  Any ideas - M4, M5, M6?  

[parabola]

I would take the bolt with me to a place like bolt-it or topfast (in Cape Town) and show them. Also make sure you get stainless steel (316 preferably, otherwise 304) or they may rust.