This is a points card for Microsoft points on your x box 360. All you do is input the code on the card and the points are attributed to your account.
You can use these points to download Xbox Live arcade games, Added content to games such as extra multiplayer maps and weapons and extra vehicles etc. music tracks and video's off market place. This is the best point to pound ratio offer i've found.
Play.com 1 point = £0.81 £16.99 = 2100 points
Xbox.com 1 point = £0.85 £42.50 = 5000 points (same for all options)
as you can see the saving might be small per point but when ya taking 2100 points its pounds!!
The points are deffinately worth gettin as the added content will prolong the longevity of any games life span and keep you playing for longer. Thumbs up