Pleats air filter also named Z line air filter.  

Normally this type z line filter have primary pleats filter, secondary pleats air filter. or active cabon pleats air filter. 

The merv 8 pleated filter media is synthetic fiber filter or coarse effect cotton. 

Due to this air fiter media very soft, so normally it need metal screen for protect. 

The pleated air filter frame have  Aluminum frame, Galvanized frame,  or cardboard frame. 

Efficiency from G1, G2, G3, G4, F5, F6, F7, F8 comply with Arshae 52.2 and EN799.