95" Aluminum Upper Arm with 90 degree corner - Replacement Tarp Arm Item #: 9309 Part #: ASAWC Upper corner arm for truck tarp systems is made of lightweight, heavy-duty aluminum. Measures 2 1/8" wide and 95" long. 90-degree corner adds 5" length. This full-length side arm is typically what you need for dump truck systems on beds from 18 to 38 feet.