This set was released in 2005 as part of the Star Wars Episode III: Revenge of the Sith line. I bought this as a brand new set from Toy Station in Serene Centre for S$19.90. There are 108 pieces in all, including some unique printed bricks.
The walker is based on the All Terrain Recon Transport (AT-RT) seen in several Star Wars films, comic books and video games. It features an open cockpit for a single driver and cannons which swivel. Unfortunately, it is not to scale and is much larger than it should be.
One mini-figure of a clone trooper in Episode III armour is included. A unique feature of this figure is the 91st Recon Corps. markings consisting of a red circle and a sword pointing downwards through it which is only available from this set. It would have been more appropriate for a Kashykk trooper to be riding this as portrayed in the film.
Overall, it is well-designed. You would be able to build a whole division of walkers if you buy several of these sets.
AT-RT with clone trooper (91st Recon Corps.)
Clone trooper (91st Recon Corps) - front
Clone trooper - rear
Alternate modes you can build with the same set