One of the best rear shock absorbers made for Montesa, and the most commonly fitted aftermarket.

The Ohlins shock is fully rebuildable allowing it to be serviced keeping it in top condition, it also allows the shock damping characteristics to be adjusted to suit the rider. 

It comes with spring pre-load adjustment and a external damping adjuster.
 
These are also built and set up to order, and is usually around a week turnaround time but it can vary.