A three piece shock setup found on most toy and some beginner hobby RCs is one where there are only three pieces: upper, lower, and a spring of some kind. These shocks have no oil, rubber seals, or extra hardware etc. This type of suspension really doesn't have the ability to take a hard bashing and there are rarely any replacement parts if something should happen to break. This is especially the case for the toy-grade RCs. Kind of a "what you see is what you get."
On intermediate and high-end hobby-grade RCs the shocks and the entire suspension setup are not just for show. They play an integral role in how the RC handles and how well it performs under different terrain conditions. The suspension setup on these types of RCs as a whole also has a lot of variable options. This allows the owner a lot of leeway when it comes to tuning and tweaking. You can adjust things like ride height and rebound rate of the dampener shocks due to the type of oil used and the strength of the coil spring (which in some cases is indicated by color).
Some of the common parts of hobby-grade RC shocks include:
- shock caps
- piston
- shock shaft
- shock cylinder / body (which holds the shock oil)
- shock spring
- various clips and retainers to hold it all together