Specifications

Back-Off Sub:
There is usually a left hand thread for tool joint at the upper part of the body,

 Back-Off Sub

 

 

The back-off sub is also named back-off spear. There is usually a left hand thread for tool joint at the upper part of the body, while the expansion sleeve has right hand thread. The guide cone at the lower part can make the expansion sleeve of the sub conveniently screw the fish connection.

Raising the drilling tool, the expansion sleeve can hold the fish firmly, then reverse.