Beeswift ARC Compliant Long Johns (Under Garment) is Flame Retardant. Anti-Static. Made from 210gsm 60/40 Modacrylic/Cotton with anti-static. Inherently flame retardant fabric. FR properties will not diminish with repeated laundering. Soft comfortable fabric with contrast FR sewing thread EN ISO 13688: 2013 EN 1149-3: 2008 EN 1149-5: 2015 EN ISO 11612: 2015 (A1 B1 C1) EN ISO 14116: 2015 (3/5H/40) IEC 61482-2-2009 EN 61482-1-2-2007 (Class 1 4 kA) - Box Arc testing EN 61482 - 1 - 1 : 2009 (EBT50 5.9 cAL/cm2) Open Arc testing. Each garment is independently tested to both Box and open ARC standards. Click ARC production is covered by article 11B certification.