Denki Blocks! has been published for the following phones:

Nokia 3410, 6310i, 3590 and 7650 and through Sprint phones in the US.
Siemens M50 / MT50, C55 and SL45i, SL42.
Samsung Rainbow/A500, N400, LG5350.
Sanyo 4900. Sharp GX10.
Retail Packs can be purchased from high street stores.
These electronic devices allow you to play with Denki digital toys and games.