Ten-pin bowling ramp in which a bowler will use two hands and push the ball down the ramp onto the lane. There are three widely recognized delivery styles used while the ball is released onto the lane. (See article: Bowling form.) These are the "stroker", "cranker" and "tweener" styles. Lesser used (and newer) styles include "no-thumb" and "two-handed". Strokers often keep their shoulders square to the foul line and their backswing generally does not go much above parallel to the ground. This type of delivery reduces the ball's rate of revolution, thus decreasing its hook potential and hitting power. Strokers rely on
Ten-pin bowling if synthetic. The top of the pin shall have a uniform arc with a radius of . The USBC also has regulations governing the weight distribution of the pin from top-to-bottom. Pins are allowed one or two "voids" (holes) in the belly area (which can be viewed if the pin is cut in half from top-to-bottom). The voids are needed to balance the narrower top half of the pin with the wider bottom half. Without them, the pins would be too bottom-heavy to fall properly when struck. In addition, a standard regulation pin may lean no more than 10 degrees