Mag Base Indicator Holder with Articulating Arms Specifications include... Base Dimensions 2.36" L x 2.00" W x 2.17" HT 11" Arm Length 180 lbs Magnetic Pull Features include... Arm has 3 articulating joints that can be locked with a single hand knob. Use with 3/8" and 8 mm stem diameter indicators. Magnetic bases have On/Off switch.