We offer coffee valve,one-way degassing coffee valve,Semi-automatic coffee valve applicator machine,coffee valve kraft paper coffee bag ,drip coffee filter... Why the coffee valve with have filter on it ? Some of our coffee in the coffee bag are ground coffee, which we also called coffee powder. The filter can protect the one way coffee valve , and make sure their function—releasing co2 outside the coffee bag would not be the ground coffee effected. If the ground coffee stuck into the coffee valve Contact us to get more information; hebe@colorsuns.com william@colorsuns.com www.colorsuns.com