Purolator offers a full line of hydraulic reservoir breathers and filler breathers. These products filter the air which breathes into and out of the reservoir, helping to maintain hydraulic fluid purity. For detailed information, request bulletin #FB-5/01-2K. BRF Series Reservoir Filler Breathers Chrome plated steel cap with plastic or steel basket. Self-tapping screws mount filler breather to reservoir. Options include dip stick, locking tabs and basket length. 3.25" diameter. Basket lengths from 3" to 8". Available in 10 and 40 micron filtration.