The SC1211G 4A guard column has a polystyrene divinylbenzene (PSDVB) base with a sulfonate functional group and calcium counterion. Recommended for use with the SUGAR SC1211 column. Fulfills USP-NF L19 and L22 requirements. Shipping solvent: 75:25 water:ACN. Stainless steel coupler 220-91524-97 or PEEK coupler 220-91524-99 (double ended) or 220-91524-98 (PEEK tube and fittings) is required.