Use this work stop with vises to hold pieces extending beyond the vise jaws. It is the perfect size for 3" and 4" vises. It can also be used in other setups using angle plates, jigs, and so on. Made of hardened steel Column is 0.47" diameter and 3.94" tall Base is 1.57" wide, 2.76" long and 0.47" thick Rod is 0.375" diameter and 6" long Machinists' jacks are used to support odd sized or odd shaped objects. Use them to support the ends of long workpieces that extend beyond your vise jaws. Use them to support the edges of items that you are clamping with your clamping kit. The machinist's jack includes lots of parts that you can mix and match to meet your needs. Two extension bases Auxiliary pointed screw Inner and outer V bases This jack is about 1" in height when retracted and can extend to about 2" which should be appropriate for a 3"-4" milling vise on a mill table. *Note: Work Stop Requires appropriate stud, nut, and t-slot nut to mount to your table.