Home / Arms / 1RI-H639 BK Adjust. 1RI-H639 BK Adjust. Category: Arms Description Spec Sheet Description Spec Sheet: 1RI-H639 BK 80-96 Adjustable Arm Related products Arms 1RI-593B Arms 1RI-H634 4D Adjust. Arms 1RI-PU Pad 159-1 Arms H-637S S2 Adjust.