Outerwears for what the K&N's or UNI's? UNI's don't use outerwears, like mentioned earlier the outer layer (red) acts as an outerwear. My bike has run a UNI filter in the stock airbox for 15 years and NEVER has there been any shit getting into the intake. It's been riden on sand, dirt, mud, snow and nothing has ever happened. Yeah it looks like shit but it works.