Strong double socket arm with plum-shaped anti-theft lock design, after the safety knob is tightened, use the plum key to lossen it. socket arm overall length of 3.4" and socket-to-socket length of 2.6" 1.5" Ball double socket arm attaches to any 1.5 inch/ C size/ 38mm ball mounts components, mounting bases and device holders; double ball and socket technology allows for near-infinite adjustability of your mounting system Aluminum alloy double socket arm made of powder-coated, marine-grade aluminum for durability and reliability in the most demanding environments 1.5" Double socket arm for fish finder/ motorcycle/ bike/ car/ engineering machine/ tractor/ agricultural machinery/ forklift and more Backed by a lifetime warranty, if you have any questions about our Double Socket Arm, please contact us by email, we will help you solve it Strg Double Socket Arm with Dual 1.5" Ball Sockets, 3.7'' Long Double Socket Mount Compatible with RAM and 1.5" Ball Systems from Arkon, Bold and Tackform Enterprise Series