ERF 2″ Filter S-series for Quark Chromosphere

Player One S series filter using high quality optical glass substrate and multi-layer composite coating technology, which has excellent optical performance in astrophotography. 2 inch ERF filter ( Energy rejection filter for Quark Chromosphere） This filter is an assistant filter, design for Quark Chromosphere (Ha verstion) , intend to reject energy and extend life time of your Quark. 2″ ERF filter must working on 6″ or smaller refractors. (DO NOT use it on eyepiece for observing)