The MaxFlow® filter for the MS500i was developed and tested for nearly two years. Initially released as the "summer" version with a partially exposed filter element, the current "all season" version has an integral brush and moisture baffle that fits neatly under the factory cylinder cover. In many cases, user modification to the cylinder shroud cover or baffle IS REQUIRED to prevent contact between it and the MaxFlow cover.
Our customers have advised us that there are "fake" MaxFlow 066 filter kits being offered online. They are not approved for use on USFS lands and are of inferior quality. Purchase from a trusted source, from your Stihl, dealer or here direct at MaxFlowfilters.com. All our kits are 100% MADE IN USA!!! Thank you for your loyalty.