The STP filter was the only one available for a 2010 Prius at AutoZone. The base of the STP is a solid piece of plastic that clicks in place when placed in the engine oil housing. It has a high 96% efficiency which also influenced me to purchase this filter rather than look somewhere else. Last, if you look carefully at the OEM filter you will see the edge of the filter pleats are not covered in hard plastic, and would allow dirt to pass the edge of the filter.