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 set by human pinsetters or "pin boys", but with the invention of the semi-automatic pinspotter in 1936 (usually just the "spotting table" component), the process became much easier. In 1946 AMF Bowling launched the first commercial fully automatic pinspotter, the AMF Model 82-10, followed closely by the more developed 82–30 model (still in common use in the 21st century) to replace the earlier Brunswick semi-automatic and fully manual bowling establishments. Brunswick itself introduced its own "Model A" automatic pinspotter design to bowling centers in 1955, and along with its successors (A2 and "JetBack", both with quicker delivery of returned balls