Covering the solutions you have in our 40" Black Iron or Stainless Steel tanks when they're not being used keeps dirt and contaminants out and extends solution life by preventing evaporation for a nice $$$ savings to you. Has a thick, rubber seal to compensate for slightly bent or warped tanks and still gives a tight fit. Available in 18 gauge steel or stainless. Mfg: Brownells SPECS: 18 gauge steel or stainless steel. 40¾" (103.5cm) x 6½" (16.5cm). Will not work on tanks with heat saver shields.