Shock Types

-Mono Tube (non-Bulb Top)
Mono tube non-bulb top shocks, or referred to as gas shocks, that uses a single tube body design. Inside this body is and oil column and gas column that's separated by a floating piston. There is a fill port in the gas column that can adjust or set the gas pressure. The gas pressure is usually set by valving but can also be used to adjust rod force. A down side to a mono tube is that a dent in the shock body will create serious issues or a failure of the shock if not caught soon enough.

-Mono Tube (Bulb Top)
Mono tube bulb top is identical to the mono tube non-bulb top but with a bigger gas chamber. This is beneficial when a shock has a lot of travel or the shaft of the shock is ran in a compressed state, like a RF. The bigger gas chamber builds less gas pressure through travel and has a more consistent rod force then compressed. Also has more surface area for cooling.

-Mono Tube (Base Valve)
Mono tube base valve shocks are identical to the mono tube bulb top, but has a stationary shim stack that decreases the pressure the floating piston sees during compression. This allows for less gas pressure, thus less rod force. This also provides a crisper turn around from rebound to compression giving the driver better input into what the car is doing.

-Twin Tube
Twin tube shock design is exactly how it sounds. It uses 2 tubes, an inner and an outer tube. The outer tube just houses the gas bag and oil. The inner tube, or pressure tube as the industry calls it, is where the piston and valving runs. A twin tube shock has a base valve shim stack at the end of the pressure tube, this valve stops the oil from cavitating. The pressure tube is wrapped with a gas bag that does the same thing as the mono tube, and take up the volume of the shaft entering the shock body. Some draw backs to a twin tube are poor heat loss, smaller piston, and non adjustable gas pressure.