The SYM-2 was an evolution of the SYM-1.

From the press release:

Synertek has introduced the SYM-2, which offers a choice of microprocessor (6502, 6809 or 6802). The SYM-2 is software compatible with the SYM-1 and adds some hardware features: on-board power supply , eight toggle switches for input, eight LEDs to display outout in binary and cassette interface jacks. Hardware compatibility between the two SYMs ensure that RAM and disk interface devices that work with one will work with the other. Designed for learning computer hardware fundamentals, the SYM-2 sells for $249 from Synertek Inc.