Grizzly H3328 Multi Purpose Magnetic Base
This Multi-Purpose Magnetic Base fixes indicators and test equipment to all ferrous metal with just the turn of a dial. Locking arm attachment point measures 0.400" diameter. V base attaches to round pipe as well as flat surfaces. The side opposite the dial is also activated by the dial. Base measures 2 1/2" long by 2" wide.n You can make a variety of jigs with this base.