Rigid with a single door strap. Designed for use on 1-1/2" to 2" thick wood framed sliding doors. The slot at the top of the door strap allows for lateral and vertical adjustment. Capacity of 450 pounds per pair. Comes with two end caps and bolts to secure the door strap. Made from durable, one-piece steel, precision formed and featuring self-lubricating Delrin bearings. Packed in box.