The A models superseded the original models. The A models include all of the upgrades that were available via Service Bulletins for the KY-196/197. These improvements include the following: • Expansion to 760 from 720 (i.e. 135 to 136 MHz) • 9 channel memory • Remote frequency transfer capability The products improvements in the A models include some technical and production improvements which enhance the overall reliability of the radio. The A models utilize a different mounting rack than the original KY-196/197 radios.