Bowling ball to skid longer before reacting (hooking). Reactive cover stocks finishes include "matte" (aggressive reaction), "shiny" (longer skid distance than matte finish), "pearl" (greatest skid distance among reactive cover stocks), and "hybrid" (combination of skid distance and back end reaction). Duckpin balls weigh each, with up to three balls delivered per round (or "frame") of bowling for one bowler. The duckpin ball has a maximum diameter of , slightly larger than a candlepin ball but, like a candlepin ball, contains no finger holes. Duckpins are correspondingly shorter and lighter than their ten-pin equivalents and it is more difficult to knock them
Ten-pin bowling determining success in the sport of bowling." The USBC completed data analysis and released a lengthy report on its website (www.bowl.com) to the public in the spring of 2008. As of April 1, 2009, The USBC now regulates the chemical surface roughness of all bowling balls manufactured for certified ten-pin bowling. This specification is a direct result from the ball motion study, as the surface roughness of the coverstock of a bowling ball was the number one variable (out of 18) that affected the strength (how much a ball hooks) of a bowling ball. The radius of gyration specification has