StrongHold JP131HBC50RB-L20 J-Pro J hook with Hammer-On Beam Clamps have a patented design, featuring complete horizontal and vertical 1" bend radius control as well as 360 degree rotation. This feature prevents pinch points and degradation of cable performance. They are suitable for use in air handling spaces and are UL listed. For use with flanges 5/16" to 1/2" (7.9mm - 12.7mm)thick and 1.31" (33.3mm) max bundle capacity. Made of Nylon 6.6, are Black in color and come in packages of 50.