The Exwell 'BO' Type Shifting Tool is designed with the Keys is held in retractedposition until the Sliding Sleeve to be opened is reached during operation. As thetool string is lowered through the Sliding Sleeve, the Dogs up far enough to retractinto the upper groove on the Main Mandrel. As the Dogs down and out to theiroriginal position. The tool string should then be raised back into the Sliding Sleeveupward strain on the wireline is required to compress the upper spring, allowingthe Dogs, Dog Retainer and Spring Housing to move down ward.The Dogs should move down far enough to engage the lower groove on the MainMandrel. At this point the Spring Housing should release the Keys, allowing themto expand to engage the profile in the Closing Sleeve. Downward jar action shouldcause the keys to retract, to release the Shifting Tool and to allow the tool string tobe raised to any Sliding Sleeve to be shifted down or it may be returned to thesurface.