Fill the first container to desired level and record fill gauge reading using built-in reference marker. Subsequent containers can be filled until level indicator reaches reference marker. It's that easy to get accurate filling every time! Designed for use with lower viscosity, non-sticky, liquids. Fits any steel drum with a 2" or 3/4" NPS opening. 23" long. Plastic non-threaded 2" adapter included. Adapter allows access of a 1 1/4" hose or pipe, so filling and gauging may be done simultaneously.