... Common Mast Model: A masts, K masts (open-front masts), derricks, masts and bootstrap masts. ... Features,Common Mast Model: A masts, K masts (open-front masts), derricks, masts and bootstrap masts.A-mast ... lowered integrally by use of power of the drawworks.K-mast its leg section is "K" open face type. The ... the ground and raised or lowered integrally by use of power of the drawworks.Telescoping mast: The ...