The bosch gol 26 d professional optical level is extremely robust and ideal for outdoor use weighing in at 17kg and with its sturdy metal housing dust and splash protection ip54 it is perfect for use on site it has a built in target collimator and an integrated circular vial along with a compensator lock for easy and safe transport the penta prism makes it easy to read the circular vial and there is a large focusing knob for easy alignment there is a fast aperture for excellent staff rea