A projector's air filter prevents dust from accumulating on the optical elements inside the projector. If you are replacing your lamp, it is a good time to replace your filter. Manufacturers' suggest replacing the filter when changing the lamp to ensure optimal performance. The R9805165 filter is compatible with the Barco DP4K-60L Alchemy, DP4K-45L Alchemy, XDL-4K75, XDL-4K60, and XDL-4K30 projectors.
eBay