3M filter ventilation unit with 2 options of optional air flow (185 l / min and 205 l / min) offering more comfort for the user; use is simple and versatile; highly effective filter captures hazardous dust, mist and smoke; light and balanced design for greater user comfort; the intelligent lithium-ion battery charges quickly and is equipped with a useful charge indicator; low air flow or low battery status is signaled as well as battery charge; it also includes a load status indicator / particle filter and an air flow indicator