Metatarsal Safety Boots Using Poron XRD technology, these metatarsal boots with a robust design are S3 SRC certified, offering excellent slip resistance and metatarsal impact protection. Upper in water resistant leather. Midsole in composite and toe cap in steel. Designed for comfort. What are Poron XRD boots? Poron XRD is a revolutionary breakthrough in Metatarsal Guard Technology. Using a proprietary foam material (i.e. the yellow pad), Poron XRD is so extremely lightweight and flexible you almost don't even realize you're wearing a metatarsal guard. Guide to Safety Footwear Main Safety Properties of SRC Footwear Toe Protection Against 200-Joule Impact Antistatic to Prevent Build-up of Static Electrical Charges Penetration Resistance Energy Absorption in Heel & Fully Enclosed Heel Oil Resistant Sole COLOUR: Black FIT: Normal CERTIFICATIONS: EN ISO 20345:2011 S3 M SRC MAIN MATERIAL: Leather upper, Dual Density PU, Steel toe cap, Composite midsole protection