First of all the shocks are super long. The front shocks are longer than the rear shocks on the Losi. That's how long. This means there are a lot of suspension travel that can handle the big jumps, it also allows the car to handle really bumpy tracks. In Sweden it's very common that the tracks in the end of the day blows out and looks like the surface of the moon, full of craters. 

Secondly the shocks has two springs. This is not one progressive springs but two individual springs connected with a plastic piece. This makes it possible to mix and match different stiffness in the long and the short spring. The short spring is softer and meant to handle the small uneven patches in the track while the longer spring takes all the jumps and bigger obstacles.

The third thing, which I know some other shocks use as well, is a soft sponge like dampener in the top cap. This is to handle the change in volume and compression that happens when the shockpiston goes up and down. This makes the travel super smooth as well as zero rebound. You can set it up to have rebound as well but I like it really dead. 

The assembly is pretty straightforward and similar to many other shocks. But there are some details worth pointing out. 

• To mount the foam to the top cap apply a small amount of glue to make it stick better, even if an adhesive tape is provided.
• The lower plastic ends needs to be tapped with a thread tap because the plastic is way too hard to just screw on without having threads.
• It's important to mount the oil seals in the correct direction (see pictures).
• You have to drill your piston holes yourselves, the pistons come as whole discs. The default is 2x2.4 in front and 2x3.2 in the back.
• Good oil CST to start with is 350 in the front and 500 in the back. This is what Tim Vander Elst used at Starec.