Surveying Instruments are used in surveying, engineering and construction applications like Topcon AT-B series sets and Auto levels. The AT-B4 automatic level features further enhanced reliability under all environmental conditions. With the IPx6 rating, the instrument is protected against powerful water jets from all directions, making it fully resistant to driving rain and splashing water. The Topcon AT-B4 quickly levels and stabilizes the line of sight with its finely tuned magnetic damping system, in spite of any fine vibrations present when working near heavy equipment or busy highways. My company manufacturing and supplies many surveying instruments, you can see more.... website: http://labtechonline.com