The clamp on this V Block mounts with two "Allen" screws - it can be mounted in three positions on top and one on the bottom of the block. The block is 3 1/4" wide x 2 3/4"long x 2 7/8" high. It is in very good condition and has GREAT PATINA - there is some light staining, but no rust - it is MUCH NICER IN PERSON, WHICH DOESN'T SAY MUCH FOR MY PHOTO ABILITIES. "Clauss" is heavily incised on both sides. A very nice quality tool not seen often - I hunted extensively on the net and could not find another example. Thanks for looking - if you have a few minutes, I have many other tools listed in my Ebay store, including more machinist tools from the same Gerstner toolbox as this v block. (LS7/Flt Bx 4- 1022)