Rigid one-piece construction with permanent powerful magnet holds secure. No need to make extra fixtures to set indicators. Unlimited versatility —used with coolant systems, lamps, etc. Side arm clamp holds all AGD dial indicators and all test indicators with a 1/4" diameter stem. Base width: 2-1/4" Base height: 2-1/8" Base depth: 1-3/4" 40 lb pull