ATAIRSOFT FMA EX Headset And Helmet Rail Adapter Set GEN2 DE TB998 Fast! 7-15 days to US! Expedited Available! 100% Brand New! For Airsoft Only! 100% Brand New. for use in the EX helmet series; for MSA headphones; very simple operation: guide rail need not tear open outfit, use two screws, nut is placed within the guide rail; It does not include demonstration stuff.