Looks like an altered 2105 to me. I guess with the success of the rack mounted 2300 Mac started building 2120's and 2200's. I rack mounted 2205's 2125's, 2255's 2155's 7150's , 7270's and 7300's all the time using the panics in fixed locations. Only a few portable discos used Mac 2120's and 2200's . The amps were just getting too heavy. Ever try lifting a 2600 by your self or a 3500. Only once. When building discos in Mexico the Mexican laborers would throw them on their friends backs to carry them up flights of stairs as the elevators weren't working yet. Little guys not much taller than 5 ft were carrying 2300 's with little effort it seemed. But then they carried large sacs of cement, plaster, and tiles up the stairs the same way.