The BrownBox FTF . "full time Filter"upgrade . we've added an integrated EMI/RFI noise filtering circuit to the unit . Note if you own an earlier version BrownBox unit we can modify it to accept the new Filter Module . to take advantage of this update Mod, a fee for parts and labor of $25.00 is charged. Directions : ( carefully pack ) your BB unit and include a prepaid return label inside the box. it is strongly advised that the shipment be insured for the full replacement value.