Allows fast and clean filling of DEF (Diesel exhaust fluid), also known as ad Blue. Features special threaded connector to fit All standard DEF systems, elbow adapter to create angle, shut-off valve to prevent spillage, air-bleed line for fast flow, built in screen to prevent contaminants entering system. Funnel body features wide-mouthed opening & built in handle. Allows easy, one-man, filling with large (10L) containers, saving time & money. California prop 65 - warning, this product contains chemicals known to the state of California to cause cancer, birth defects or other reproductive harm.