The Hammer Black Widow Spare bowling ball is the deadliest polyester ball around! It features Hammer's proven Gas Mask Core with a shiny polyester coverstock to give the bowler more hook and core motion in a polyester option. The Gas Mask core is used in 14-16# weights, but has a standard pancake weight-block in 12# and 13# weights. This hot looking ball is sure to catch the eyes of Hammerheads across the world!