Full Pneumatic (SF). Recommended for the greatest possible protection to both loads and floors. If you transport fragile materials or parts, or if you move delicate instruments over rough floors, you should consider a pneumatic tire. Full pneumatics cushion the load on air, just like an automobile. They must be properly inflated as indicated in wheel table. Can be filled with urethane foam to make them deflation proof, but foam has no effect on capacity. Suitable for extended service.