Our Foam Cell Pro shock absorbers feature a tough, military spec, big bore 3? twin-tube shock, the largest, strongest shock on the market; they are nearly indestructible, carry no internal parts which can jam, require little to no service, and are rebuildable. The Foam cell pro shock is filled with premium grade FUCHS oil and our foam cell sleeve technology. The foam cell sleeve, impregnated with millions of tiny bubbles of nitrogen, maximizes oil and thermal carrying capacity and eliminates high internal pressures found on regular nitro gas-shock absorbers.