The aFe 28-10243 is a black Filter GUARD pre-filter from aFe's MagnumSHIELD line, built to slip over the outside of a matching aFe performance air filter. The manufacturer lists it for the 72-90040 filter, along with 21-91128, 24-91128 and 72-91128. The fabric is a dry-weave polyester that repels water and dirt with minimal effect to air flow, based on the manufacturer's pages for sibling Magnum SHIELD part numbers. Its main value is protecting the filter underneath, so a buyer running a dusty or off-road setup gets more life from a filter that costs more than this wrap.
Pre-filters protect your performance air filter and extend your filter cleaning intervals, which means fewer trips to clean or replace the main element. Because the cloth is washable with soap and water, the wrap can be reused instead of replaced. Expect to clean it often in harsh conditions: owners on user forums who ran a similar AFE pre-filter reported the cloth was pretty clogged at the end of a season of use, so plan on regular washing if you drive in dust or desert terrain.
The manufacturer's fitment table lists it for the 72-90040 filter, and also for 21-91128, 24-91128 and 72-91128. Check the SKU on your current filter before ordering, because each pre-filter is made for the filter it is paired with.
The manufacturer's pre-filter pages for sibling Magnum SHIELD part numbers say the fabric can be washed with soap and water. Owners on user forums recommend washing it regularly when driving in dusty conditions.
The pre-filter is a slip-on part: you pull it over the outside of the air filter and secure it with the pull tabs, so no drilling or modification to the intake is required. Before you start, confirm that the filter in your intake matches the 72-90040 family listed above, since a mismatched wrap will not sit correctly. Remove the filter, clean the wrap, and reinstall it the same way each time you service the air filter.
