Bilt Youth Defender Knee Guards The Bilt Youth Defender Knee Guards utilize a vented multi-panel hard shell exterior and fully perforated high density foam interior to create comfortable and effective protection. Hinge joint flexibility and elasticated straps with hook and loop adjustments allow for excellent mobility and customizable fit. A low profile allows you to wear the Bilt Knee Guards under or over your pants. Features: Vented multi-panel hard shell exterior covering elbow and forearm Fully perforated high density foam for max venting Breathable, wicking, poly-lining Hinge joint flexibility Elasticated straps with hook and loop adjustments Low profile can be worn over or under pants One size fits most