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)