The SitePro 1701-04 tilting 25mm mini-prism is inexpensive and designed to be set-up and left for monitoring, mining or tunneling sites. Consant of -17.5mm offset, 86mm height Provides longer range up o 2,000 ft (600m) Target with mini-prism tilts and rotates 360-degrees Mount with swiss-style male tip or swiss-style quick release adapters