The Filler/Breather Weld Flange Adapter from Buyers Products allows you to install a filler/breather cap to the top of your hydraulic reservoir. It's ideal if you are fabricating your own reservoir. Made of steel or aluminum, the adapter welds to the top of your reservoir. It features standard 6-bolt, 2 in. center design to fit most standard filler/breather units, and provides a 1 in. rise.