Aeromotive 40 Micron Stainless AN-12 Red Filter 12343 - AN-12, 40 micron stainless steel element, red anodize finish. An inexpensive insurance policy to protect your investment, proper filtration is key to fuel system performance. Engineered filter solutions are required to achieve protection with minimum restriction. For 200 - 3,000 plus HP applications, our filter assemblies offer unmatched flow, ease of installation and maintenance, along with the impeccable machining and finish you've come to expect from all Aeromotive components.