Bullwhip Replacement KEVLAR String Popper Cracker Professional Grade and Length KEVLAR for Bull Whip (7 pieces) #FP3 7 pcs. Yellow KEVLAR String Popper for Bullwhip Replacement Cracker Professional Grade for Bull Whip Material: KEVLAR Color: Yellow, Length: 11 inches Great Value: 7 Pieces This is the toughest material we could find. Lasts longer.