at the moment its 3/4".(2 3/8" E-G)there are 5 adjust nuts on each saddle,3-height ,1 lock & 1 for lateral saddle adjust. there is about 1/16 " on either side of saddle which makes it flexible. there are mounting holes under saddles for fixed mount.Im drilling 'cause I like the flexibility. slots are small so some file work is necessary,which I like. i remember it was about $150.00. but that was several years back, I think.