Features: Viscoelastic memory foam: after an impact or deformation of the foam, the protector will quickly revert to its original shapeMultiple impact compliance: even if the same area of the protector receives repeated impacts, the protector maintains if fully functional capabilityAdaptive absorption: the air within the cells of the protector allow progressive absorption of energy as the material becomes more firm as it compressesClimate stability: SAS-Tec Visoelastic foam does not break down under high temperatures and can withstand up to 212 degrees FahrenheitEnvironmentally conscience: partially made of recyclable materialsSold as ONE PAIR (except back protectors) certain armor doubles for multiple abrasion zones i.e. elbow, knee means that armor works for both elbow and knees