1:PU or normal foam filling 2: waterproof cover 3: Factory direct price wheelchair back support1.High density memory foam / HR foam core2.Breathable design and pressure relief3. Waterproof zip-off cover. Can make customer’s logo on cover.4.Certificate: ISO9001, BS5852, BS7177, CFR1633, CA117, ASTMD3574, PONY Testing.We are the professional manufacturer of wheelchair parts .