Tightlok threadbar bolt is composed of hot rolled ribbed bar, high strength plate , damping nut , yield tube, washer , and other accessories. Usually used in thick coal seams with very high stress and large Deformation. Features: (1) High tensile strength and good support capacity which can prevent the roof from sinking and sliding. (2) Fast and easy installation by mechanized tools. (3) Used together with resin cartridge for permanent support. (4) Sharp end device makes installation easier and faster. (5) Left hand thread direction available. (6) Specially "sandwich"device can buffer and release the pressure.