CNG1 Selective Recovery Resin Media is designed to recover gold from your Acid gold post plating rinse tanks. The resin media is used in our GRS1 closed loop gold recovery system or any other closed loop system.. The gold is filtered through a column containing the AG1 resin media which uses ion exchange technology to reclaim your expensive precious metal gold. The resin can then be refined for a profitable return. This is sold in 1/4 cubic foot bags or 1 cubic foot boxes.