This is the new edition Ninjago starter set. I would recommend buying either this or LEGO Ninjago 2257: Spinjitzu Starter Set as these sets work out cheaper than buying two individual characters and come with the arena.
This set features Rattla, a grey and blue snake tribe member and Cole ZX, a ninja in a black suit. Each character has their own spinner and three weapons. The spinners in this set are the new version ones which feature crowns, additional fancy lego circles that attach to the top of each spinner. There is also extra space underneath each spinner so that you can attach some of the extra spinner components that come in the booster packs (spikes, chains etc to customise the spinners). The weapons in the new series are also a bit more exciting, there are bits to attach together to make them look pretty impressive, my son likes the snake weapon and the one with the orange spikes (or carrots according to my four year old). There are also some game cards to make game play more exciting.
The arena is basic but effective. It is easy to construct using thin black rods and green connecting pieces. It is probably worth noting that you need a hard floor or table top to play this on as the spinners obviously cannot spin on carpet.
The aim of the game is to basically put both characters on their spinning tops and set them spinning at the same time, the first character to knock their opponent off their spinner is the winner.
The game is simple but fun and can get quite competetive. My son has also got some additional characters and spinners and we like to send them all in for a free for all, we also have the battle arena
LEGO, Ninjago, 3D Battle Arena, Including Sensei Wu Spinner which does the same job as the one included in the set but is a bit more exciting to look at and can be used on any surface so is ideal for my son's carpeted bedroom.
These lego sets are a lot of fun and I would highly recommend this as a good starting point for anyone wanting to start collecting ninjago.