The drawworks conform to API Spec 7K, are complete in series and have single and double drum and multiple shaft structures adn driven mechanically or electricalally, the models as below: JC14, JC18/11, JC21/11, JC28/11, JC 20, JC 30, JC40, JC50,JC60,,JC70,JC30DB, JC40DB, JC40DJ, JC40DZ, JC50DB,JC50D, JC70DB, JC70D etc.