from the fish website:
THE COOL JERK:
The Cool Jerk is a length of 5/32" cable, 32" long, with a loop swaged into each end. Use it to clean Heads, RURPs, and some pins by clipping into the piece and looping the other end over your hammer head. Take a wild swipe at the air and when this baby comes taut, action is assured. The low stretch of the cable, coupled with the velocity of the hammer mass make for a mighty force at the offending piece. Plus, on those rare occasions when the piece rifles out and the whole ensemble hits you in the arm, it gives you something to think about besides your next lead. Think of it as "distraction through pain" therapy. $6.75 ea.