Looking through my stash ...... the DLE 30 / 35 standoffs are 60mm, the 55 has ones that are 68mm. The 55 standoffs are considerably heavier duty than the ones for the 30 though both are tapped for 5mm bolts on both ends.

DA makes some nice standoffs in 1.25", 2.5" and 3". These are tapped 5mm on one end and 1/4 - 20 on the other. I have others on airplanes but I can't access them right now.