Drilling Hook is provided with a braking device to lock up & lock out the body. The body, the bail, and the bail support are cast with special alloy steel. Equipped with a hydraulic snubber assembly toprotect drill pipe joints when making up/breaking out connections.At the hook there is a reliable safety device. 

Joining the travelling block and the hook together reduces overall length to satisfy the requirements of a top drive.
The shafts of travelling block are forged with alloy steel provided with a lubrication hole of bearing for one sheave.
The grooves of sheave are intermediate frequency quenched so as to improve the surface hardness and prolong the service life.
The sheaves are equipped with double-row conic roller bearings. Each bearing has its own lubrication channel.
The hook block assembly conforms to API Spec. 8A /8C.
There is a reliable safety device at the hook.
The primary-load-carrying parts of hook are subject to NDE test.