All subs made by KINGWELL are API inspected and certified. 

 

Subs are shorter components of the the drill string, averaging only four feet in length. 

 

Most subs are used as an adapter between two different connection types in the same drill string. Often times the connection on drill pipe will differ from that of the bottom hole assembly (drill collars and heavy-weight) and a crossover sub must be used to adapt the two different connections. 

 

Another common type of sub is a bit sub. A bit sub is a sub that is used just above the bit and serves as a crossover between the drill collar connections and the bit connection, and it also houses the float valve