Fowler 52-585-075 Magnetic V-Block with On Off Switch. Overall dimensions are 2-3/8" wide x 4" long x 3-7/8" high. The On-off switch is for positioning and removal. This Magnetic V-Block features contact faces that are precision ground. The V-holder will hold itself to work on any flat ferrous surface. Holds varied shaped workpieces so that light machining operations such as grinding, boring and tapping can be carried out with considerable savings in set-up time. This magnetic block has a Permanent, powerful magnet. Faces and V accurately ground and features working surfaces that are hardened to 35-45 HRC. The holder exerts a magnetic force on the upper, lower and V-channel surfaces. Magnetic force is simply switched off by means of a lever. This block includes fitted carton box. This product has 1 year warranty offered by Fowler precision. If you experience any problem contact Fowler directly for warranty claims. Fowler, an American company, manufactures inspection and measurement instruments such as electronic indicators, calipers, bore gages, and digital scales. The company, founded in 1946, is headquartered in Newton, MA