DQ50 Top Drive VFD Electric Top‑Drive Unit for 5000m Medium‑Deep Drilling Rigs Typical Feature of DQ50-BQ 1. Folding guide Rails: Top drive installation is safe, quick and convenient. 2. Equipped with 360° swivel head rotation function. 3. The pulley adopts a double-wheel structure to avoid single force on the roller and extend the service life of the roller. 4. IBOP Rack and Pinion Drive Mechanism: Ensures precise and accurate switching of IBOP (Internal Blow Off Preventer).