100% non-toxic, environment-friendly, non slip, even sweat; Lightweight, high-density, strong foam, durable and beveled edges provide soft grip. These lightweight and supporting foam blocks are made of durable foam with slip surfaces and beveled edges for easy grip. Damp proof material can isolate bacteria; Deepen and lengthen your stretch and perfectly align your posture, suitable for all fitness levels; Use under your hands, feet or seat (meditation) to ensure proper alignment, secure support and change posture to suit your level of flexibility - if you feel tight, don't risk injury, grab one or two building blocks