STR'Comfort' Race Boots - Fire Retardant SFI 3.3/5 Approved. STR Racewear is manufactured under strict quality control procedures. SFI approved to SFI 3.3/5 Standard with approval labels. · Suede leather outer, lined with soft fire-retardant nomex fabric.· High-grip moulded rubber sole, resistant to hydrocarbons. · Manufactured to a high standard. ADULT RACE BOOTS SIZING CHART. The item "STR Oval Race Boots SFI 3.3/5 Approved / Racing / Rally / Fire Retardant Adult" is in sale since Tuesday, March 5, 2019. This item is in the category "Vehicle Parts & Accessories\Clothing, Helmets & Protection\Car & Kart Racewear\Race Boots". The seller is "mcgillmotorsport" and is located in Kirkcaldy, Fife. This item can be shipped worldwide.