A modular synthesizer format created by PAiA and intended to be a low-cost format. The format uses a module height of 5.25" and a horizontal unit of 3", although most modules are at least 2U wide. 3.5mm phone jacks are used for patch cord interconnects. As originally specified by PAiA, the format called for ±18V unregulated power, with voltage regulators on each module. However, Blacet Research, which currently offers the largest selection of modules in this format, specifies ±15V regulated power, using the same four-pin MTA-156 connector as the MOTM format. The current PAiA 9700 series boards can be modified to use this power by bypassing the modules' on-board regulators.

In 2006, Synthesis Technology began offering modules in the Frac format. In addition, Cynthia and Bridechamber offer some modules in this format.

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