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

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

04Thread connections are performed with stress relief grooves

05phosphated threads applied

06with  slip & elevator recesses