2 ½ inch (62mm) diameter0/-30 mm offset5/8 inch - 11 inches threadAdjustable brass knobDurable padded case The XGeology Prism is an all metal prism assembly for land surveying in conjunction with total stations. It is fully compatible with leading manufacturers such as Trimble, Sokkia, Topcon, Leica, Nikon, Pentax, etc. The heavy-duty 2 1/2" (62.5mm) diameter silver-coated prism is sealed in a strong canister to prevent water and dust from getting inside and has a 0 or -30 millimeter offset and 2.5 arc second accuracy. The all steel high visibility (flo orange with black and white) target is 5 1/2 x 7 inches (14cm x 18cm) It incorporates a simple locking mechanism with tension adjusting brass knobs that's easy to set while adjusting the prism and target tilt. Stainless steel hardware to resist rust and increase visibility. Its brass thread adapter can be mounted to any 5/8 inch - 11 thread pole or tripod. New orange color 0/-30mm tilt prism set includes padded carrying case, all metal construction, lens cover, 5/8 x 11 bayonet adapter, lock knob and weather proof prism. Will work with all distance measuring devices. Comes with padded nylon carrying case.