Yes There are two - one set parallel and one set perpendicular to the jaws. The vise comes with two keys and the screws used to fasten them to either set.
According to the spec sheet they are 14 mm wide. I cannot measure this accurately now since the vise is mounted and trammed and I do not want to remove it. However a rough check agrees with the 14 mm spec.
In my case the T slots on my mill are only 8 mm so I modifed the protruding portin of the keys ti fit the slots while leaving the inserted portin at the full width.
The vise comes with 2 keys that you must install and align. The overall quality of the vise is good for the price. However I ordered a 2nd vise and the base height of the 2nd vise did not match the 1st one, it is taller. Individually they are good but yet are not the same. That's where there q.a. seems to be lacking.
Please compare descriptions between 4 inch vises- with and with out swiveling base, with = 3.93 inches, without base 4 inches. Same top part, only difference is swiveling base which is accurate 3.93" or 4.00" also jaw height 1.26" or 1.3" ?
the screws holding the vise jaws in place are metric (maybe M8). the slots to mount the vise to a mill table can accept up to a 1/2" bolt. the 4 inch vise jaws are not on the same bolt pattern as the imperial jaws that one would buy at US shop tools for a Kurt 4" vise.
I machined my vise by opening up the holes to 3/8-16 on the same bolt pattern as the Imperial vise jaws. i mounted my vise with 3/8-16 bolts and T-nuts.
