RAM Single Socket Arm with Metal Knob 1-2" NPT Threaded Hole (RAM-200-1MU) (sku 55079)PRODUCT INFORMATION BALL SOCKET SIZE C Size (1. 5") WEIGHT CAPACITY 4 lbs MATERIALS Marine grade aluminum PACKAGING TYPE Poly Bag WEIGHT 0. 63 lbs. ADDITIONAL INFORMATION Note: NPT (National Pipe Thread) is a standard used in joining pipes and fittings that have a tapered thread. As a general rule, the NPT inch size is the inside diameter of the threaded pipe and is known as the NPS (Nominal Pipe Size). The outer diameter (OD) of the pipe is shown in