The Nitelze Belt Clip Case provides total protection for your Kestrel 4000, 4100, 4200, 4300 or 4500, as well as an easy way to clip it to to your belt or backpack. It's is designed to expose only the Kestrel's sensors - so it will continue to record accurate readings while protected. The Nitelze Carry Case is made of a sturdy triple laminate of polyurethane, vinyl and nylon, with neoprene rubber inside to hold the Kestrel 4000 series snugly. The rugged clip accomodates up to a 2 1/4" belt, and can also be attached to your waistband. There's also a strong hook and loop strap - for secure and easy mounting to a backpack or harness strap.