AdirPro Compact Snap-On Prism (0.7" - 18mm) for Corners, Narrow, Short Distance and Walls - Works with Trimble, Sokkia, Topcon, Leica, Nikon and Pentax Total Stations 0.7" (18mm) Prism Size Compact Body (1.29" w x1.49" h) Only 1.08" Thick, Snap-On Feature Designed for Corners, Narrow, Short Distance and Walls. Durable Padded Case