The first jammer to break through the pack earns the status of "lead jammer". A designated referee blows the whistle twice, and skates near, and points at, the lead jammer. Once earned, lead jammer status cannot be transferred to other skaters, but certain actions (notably, being sent to the penalty box) can cause it to be lost. The lead jammer can stop the jam at any time by repeatedly placing both hands on their hips. If the jam is not stopped early, it ends after two minutes. If time remains in the period, teams then have 30 seconds to get on the track and line up for the next jam. If the period expires, it does not halt a jam that is underway.