Sig Sauer MPX/MCX 88g CO2 to 12g CO2 Converter by Best Fittings. Got the itch for a plink but you've got limited time? The Sig Sauer MPX/MCX 88g to 12g CO2 Convertor by Best Fittings fixes these issues for you, just simply connect the adaptor to the 88g port insert a 12g co2 and tighten up. Approxim..