The 1064M is a modern version of Atari's 1064 module that plugs into the Parallel Bus port in the back of the Atari 600XL. This allows you to upgrade your Atari 600XL from 16k of memory to 64k of memory in under a minute and results in your Atari 600XL functioning like an Atari 800XL. No soldering is necessary. Since modern SRAM is used, this unit is much more compact than the original 1064 module from Atari. As the Atari 600XL supplies +5 VDC to the Parallel Bus, no external power is required.