Aluminum Rieke Wrench: If you have a hard time removing or tightening the drum cap to our HAZMAT or GEM containers then you need one of these tough wrenches. Fits all Rieke 70 mm Caps and these are the caps that I use on the containers of Sunoco race gas, Gem SynDiesel, Gem Methanol, Gem E85 and GEM Biodiesel. Not for use with Royal Purple drums.