Yes, twin tube shocks have been around forever, and they also last an extremely long time.

Twin tubes have more oil (heat reduction, draws heat away from the inner cylinder where the piston is working), a 2nd outer layer (the twin tube, to protect the inner tube from damage), as well as thicker walls for more heat dissipation and less fading (the walls draw heat from the oil and the airflow over the shocks cools those walls down, like a heat sink), and they also run lower pressure gas inside, so they can have a different feel on the road. Twin tubes are better suited for higher speed corrugated roads, like in Australia, and will fade less overtime than a monotube. The debate has gone on for years. Monotubes have a piston inside a single (mono) tube, then 2mm or 3mm wall, then you're outside. So without a lot of airflow over them, they get hot. All shocks get hot though.

The bigger the shock body, bore, piston size and amount of oil, the better it can deal with heat. The bigger the engine in a car, the more oil it has to cool the cylinder walls and draw that heat away from the heat source. Look at what baja guys are using now, some are 4-5" thick bodies with massive pistons and reservoirs.

A monotube with a reservoir has a good benefit of more oil, but a regular monotube can heat up very fast and doesn't offer the internal components much protection from damage, aka stones/rocks flying up and hitting the body of the shock. Heat kills seals faster. Plus, Americans are going nuts for resi shocks, even when they don't need them, so Dobinsons was working on a race option shock with longer travel and bigger components, and you can't easily have a twin-tube with external reservoir to absorb the huge woops and bumps they have to go over. They're also much bigger, 66mm bodies, to hold more oil and handle the heat, since they can heat up so quickly.

If we offered a monotube regular shock to compete with our own twin tubes, they would probably be about $50 retail (cheap to make, less components). A lot like others out there in the US market. Our MRR shocks are $275 to $375 each.

I'll gladly sell you guys our shocks, because I'm confident in their ability and how they work on and offroad, but feel free to run whatever you want. Tons of guys on here are on the Billy Bandwagon, and that has spread through word of mouth. They're affordable, they work, and people like the adjustable height on the front. Color plays a huge role these days, go to a Jeep event and prepare to have your mind blown for colorful suspension options!!!