This is a Trilectlric A25100U UHF Repeater Power Amp providing 100W for 25W in and operating in the 450-470MHz range, which includes the GMRS. It is branded Trilectric but these were later known to be sold by Decibel and searching the FCC ID shows the approval being issued to Raveon.
From the inventory of a store that closed around the turn of the century, it was held in storage before being purchased by us. The heatsink has some hole which we believe to be where a fan was retrofitted then removed. Untested and, because vintage components can fail at any time, it is sold as-is, officially "for parts or not working" with no guarantee of functionality or completeness whatsoever.