The adjustable square slit CASR6 provided by LBTEK features M4 threaded holes on the bottom for free-space mounting, and four Ø6 mm through holes on the front face compatible with 30 mm coaxial systems. The slit is adjusted via thread pairs with an adjustment range of 0~6 mm square. Each revolution of the thread pair corresponds to 0.5 mm. Bidirectional adjustment enables any square size within 0~6 mm (four adjusters control four slit blades, each adjuster allows the slit blade to be adjusted from 0~3 mm, and the combination of the four knobs achieves any square size within 0~6 mm). When the slit is fully closed, the theoretical slit width is 0; however, due to machining and assembly tolerances, a maximum gap of 0.02-0.05 mm may exist. The LBTEK adjustable slit is made of wear-resistant die steel, undergoes blackening treatment to reduce harmful reflections, and the mating blade edges are precision-ground to ensure they are smooth and burr-free. Note: 1. If burrs or unevenness appear on the blade edges after prolonged use, gently wipe the edges with alcohol; 2. Adjust within the travel range only. Excessive adjustment beyond the travel range may cause the lead screw to detach.