depends on which one you have.
many replace the Concertone Chassis Group "B" units, with the Jensen AWM 965 or 975 model.
if your Concertone is a Chassis Group "A" unit, there's not much out there other than Concertone, to replace it.
unless you mod the opening to fit the "B" sized ones.
here's Concertone's product gallery to find which one yours is:
Concertone® Product Gallery
Dan-Retired California Firefighter/EMT
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package