This type of wheel is powered by the spinner's foot rather than their hand or a motor. The spinner sits and pumps a foot treadle that turns the drive wheel via a crankshaft and a connecting rod. This leaves both hands free for drafting the fibres, which is necessary in the short draw spinning technique, which is often used on this type of wheel. The old-fashioned pointed driven spindle is not a common feature of the treadle wheel. Instead, most modern wheels employ a flyer-and-bobbin system which twists the yarn and winds it onto a spool simultaneously. These wheels can be single- or double-treadle; which is a matter of preference and does not affect the operation of the wheel.