Design & working procedure Conform to the requirment of API Spec 7;Non-API standard type of drill collars are also available.

01 Design & working procedure Conform to the requirment of  API Spec 7

02 Non-API standard type of drill collars are also available as per client'request

03 Cold-rolled thread roots

04 Thread connections  are performed with stress relief grooves

05 phosphated threads applied