I changed the oil in my Generac generator and I decided to cut the filter and post some photos since I haven't seen a Guardian filter cut open before. This filter and SuperTech HD30 regular oil were run 111 hours in this generator. Replaced the filter with a Napa ProSelect 21394 and Quaker State 10w30 full synthetic oil (bought it cheaper at AutoZone than I could get regular SuperTech at Walmart). The ADBV is rubber, but still flexible, the inlet holes were de-burred, and I liked the shape of the rubber gasket. Enjoy.