Automatic Inline Air Tool Oiler - Extend Tool Life Improve performance & extend life of expensive air tools by keeping properly lubricated Automatically feeds small quantity of oil directly into air line, lubricates tool as you use it Galvanized steel with tough one-piece polycarbonate reservoir; see-thru so you know when to refill Installation takes just seconds, 1/4" NPT-threaded male & female input/output Easy-fill hole with brass screw, rubber gasket; capacity 1.5 fl oz