New! Save your sanity with the @lulladoll_australia sleep companion ???? New model with 12-hour battery life now in-store & online. Many white noise devices turn off after 20-30 minutes or are sound activated. Those that do play continuously do not have the comfort factor of a plush toy and are quite often machines instead. It makes no sense to wait until baby cries to try and resettle and we certainly do not want the sounds to stop just as the baby is resettling themselves through their first sleep cycle which is around 35-40 minutes in most cases. The key to Lulla’s success is the fact that Lulla is a comforter and plays 12 hours of continuous heartbeat and breathing.