The CT800 is a dedicated chess computer running open source software. Currently, you cannot buy a CT800, but you can build your own one given the extensive documentation.
The chess engine itself runs also under Windows, Android, Linux, and on Raspberry Pi. You can enjoy the engine’s unique playing style with all popular chess applications.
The CT800, rated at about 2200 Elo, is a serious opponent for any amateur chess player up to club level.