New silver plated 10pcs 90-degree monitoring prism GMP104, 1 inch L-bar reflector, suitable for total station L-bar prism. 90 degree L type prism. Fits for Leica total station and replace GMP104. L BAR prisms, maybe mounted on the tunnels, roads and bridges, dams, buildings and constructions or some other fix up places or objects for surveying, distortion, displacement It suits different kinds of total stations.