Marion McCoskey's FasTrak is a dynamic intonation MIDI keyboard retuning program. It works only with the Creative Labs Sound Blaster card. It is intended for just intonation in the extended sense, that is, intonation that uses only ratios of whole numbers but these whole numbers are not limited to products of 2, 3, and 5. Like Waage's proposal, it tunes notes according to what keys are currently depressed. The rules for tuning are stated in a chord logic file and a scale tuning file that can be customized by the user. It includes a split keyboard mode in which one section of the keyboard is used to select the tuning of another. It capabilities are similar to the Justonic Pitch Palette discussed below.