Underwaterhockey puck

This is a simplified puck for use in the sport underwaterhockey.

UWH is played on the bottom of a swimming pool with scuba-gear, a cap, glove, stick and a puck like this one. You can read more about it here: https://en.wikipedia.org/wiki/Underwater_hockey
For promotional goals I created this simplified puck to be printed at 20% scale.
These will be handed out to children together with sticks: http://www.thingiverse.com/thing:129665.
The pictures are taken of these 20% scaled prints.