Electron Cartridge Filter Replacement
-Open/Closed W/.54", Bolt Hole: 12.91" OD x 8.50" ID x 23.75" HGT Spun Bond Alum - No Spiral Adhesive, Poly Gasket.
-Used In Electron secondary systems used commonly with PM1, PM2, PM3 
-Typically each collector contains 2 
-If you are unsure how many filters you need. The pulse valve on the outside of the collector are a direct indicator of how many filters you have