SMAKN&reg; Dc/dc Converter 12v Step Down to 3.7v 3a Power Supply Module All epoxy sealed containers with Waterproof Housing; Non-isolated High efficiency: &gt;96%; Reliable, low heat dissipation max. 40 ; With overload / over-current / over / low voltage protection, stable performance. Light compact, convenient to use and transport; Auto recovery Widely used in Car device, such as LED Display, Hard Disk Player, MP3, DVD, GPS, etc