Tetrahedronal buoy for the board game Regatta. Approx. 12 mm (~ 0.5") between each corner. One face is flat to enable the piece to lay still and not roll around.
Given the small size of this piece, I recommend printing in metal to give it some weight. Prints in Stainless Steel do come out quite smooth and with no noticable printing lines. The corners will remain pointy (but not sharp).
The 3M edition of the Regatta board game came with 3 buoys, while the Avalon Hill version had 4 buoys. (Both editions used a very different buoy design than this piece). I recommend getting 4 buoys.