The Bosch GOL 20 D Professional optical level is robust, reliable & ideal for outdoor use. Due to its robust housing with dust & splash protection (IP54) it is perfect for daily & prolonged use. It offers fast aperture for excellent staff reading & a target collimator for rough alignment. The compensator lock makes for safe transport & the penta prism makes it incredibly easy for the user to read the red circular vial. It boasts erect image & a large focusing knob for easy alignment as well as friction-braked rotation. This optical level comes complete with an adjusting pin, Allen key, carrying case, lens cover & plumb bob.