Mountain K0834 Telescoping Upper Arm, Drilled (please specify bend, if any) Item #: 24774 Part #: K0834 This Mountain K0834 Telescoping Upper Arm is the replacement upper arm for the Mountain K12CSET Telescoping Electric Tarping System. GUARANTEED unbreakable, it measures 72” long and 1 ½” X 1 7/8” wide.