Lifetime guarantee Oversized 1/2-in diameter vials are easy to read Heavy duty aluminum frame assures durability and accuracy Ergonomic cushioned hand grips Surround view® vials reflect ambient light for easy-read Removable end caps designed for finish carpentry work when measuring into corners GripTight™ non-slip end caps hold level firmly in place with just 1 hand Field replaceable cover plates and vials Shock absorbing end caps protect frame