The Commodore SX-64 Computer was basically a Commodore 64, but in a portable design. Featuring a 5 inch Television screen, a built in 1541 floppy disk drive, and all the internals of a normal C64, the Commodore SX64 was a computer that could be carried around without need for extra devices.
With everything being built-in, the SX64 was very heavy, and quite difficult to lug around. Topping out near 20 Kg's, this was no lightweight computer. Originally sold for $995 (US Dollars) these days the SX64's are a rare find, and usually fetch around $400 dollars.
This unit differed slightly to the original C64. Firstly, the cassette & RF ports are omitted, so you cannot hook up a cassette drive nor television to the unit. Also, the start-up screen is different to the normal blue's on the standard C64. Lastly, some RAM Expansion carts are not compatible with the SX64's hardware. Aside from these differences, the unit is compatible with the C64, so you should be able to run any C64 disk on the unit.
You can find the SX64 below.