Support multiple cables on independent rollers with Multiple Roller Cable Blocks. All blocks have built-in cable retaining arms and a strand lock (up to 3/8" (10 mm) strand). Operate the open/close mechanism with just a quick pull by hand or from the ground with a Lay-Up Stick. Frames are durable cast aluminum or molded plastic with steel inserts on strand contact surfaces. Rollers are plastic. A space saver model is available that requires only 9" (229 mm) of vertical clearance. All 4 rollers are on one axle.