The Shearwater Elastic Straps are replacement wrist straps & buckles for the Petrel & Perdix Dive Computers so you can replace a broken or worn out strap on your computer. Sold as a pair of complete elastic straps with clips. They have a small plastic cam that engages if the straps start to pull loose & stops any more loosening. The elastic straps are approx 20mm (3/4 inch) wide & approx 350mm (14 inches) Long in its unstretched condition.