from the outermost notch to the outermost notch, in the saddles, it's 80mm (3.15ish), so 20mm (.78) at the widest. looks like you can get anything in between too. measures like it would go a small as 14mm. i originally got it so i could do 19mm spacing on a warmoth deluxe 5. and i't only $32.00 now.