With MWI combined F/J Soffit Trim, the "J" receives the metal siding. So, the painted surface is exposed and, you never see primer.

System 3 soffit panels keeps dangerous hot air out of attics in the summer and damaging moisture out during the winter months. Strong yet flexible aluminum soffit is perfectly vented to promote continuous airflow, a necessary component to keeping attics cool and dry. Optimal ventilation can be strategically controlled by alternating solid and vented panels. All components are virtually maintenance-free and covered by our limited lifetime warranty.