Therafin Arm Trough, Slide-On with 4.5W X 12L BasePadded Arm Troughs with padded contour sides provide a fully padded trough to hold the arm. 1" foam covered with black sturdy vinyl on the base with 1 2" foam covered with wipeable covered neoprene sides. Available in multiple widths and lengths. The slide on model slides over standard size armpads (up to 2 1 2" wide x 1 1 2" thick) using our adjustable height arm channel bracket.