Trango BIG BROS are light and compact spring-loaded, telescoping tube chocks which can be placed with one hand. Sturdy internal spring mechanism is released by an easy-access button, then a locking collar screws down to provide a solid, full strength placement. Any tug on the sling has a "camming" effect on the placement. BIG BROS are lightweight afford solid in all except extreme flaring cracks. Smaller sizes will save weight and space on your every day rack and numbers 3 & 4 will gain you "new found" protection in offwidths and body packing chimneys. In addition to your giant cams, tote a #4 for piece of mind on the Salathe's Hollow Flake pitch! Manufacturer's instructions for operation & care included. We offer color matched 5.5 mm Titan Cord to sling your BIG BROs w/ 3-4' per size. Made in USA.