This is the Royce 1-600 23 channel AM mobile. A compact, entry level, minimal feature (3 knob) rig that was easy on the pocket in the early-mid 1970's. It featured a volume, a squelch, channel selector and a decent sized, vertically mounted S/RF meter, which turned red when transmitting and flickered with modulation. Also included was a PA function which was accessed by putting the channel selector in the blank spot between channel 22 and 23 (which was where you would put channel 22"A"). While that was fine for straight PA capability, you were not able to also monitor CB transmissions through the PA speaker unless it was physically switched to the external speaker jack.
I first became acquainted with this model radio when Blue Bandit picked one up second hand to put in his 2nd mobile. I had just paid $100 for my Pace 223, and Bandit ended up getting the Royce for $75, and I was bummed because I liked the Royce better because it had a meter and the Pace did not. But the Royce had really anemic modulation with a stock mic, and it took the addition of a Turner +3m to wake it up. I would later borrow this radio from Bandit for about a month, when I was in-between radios in the fall of 1974. It was a fair performer, with a decent receiver, and about average in adjacent channel rejection.
The Kris Valiant was a clone of this radio, and the chassis could also be found in the Midland 13-879 base radio.
I picked up the radio pictured in 2017 from a donation from Night Ranger in South Carolina. It's in pretty good shape except for some fading on the meter card. On a scale of 1 to 10, I would rate the Royce at a 4. Not all that bad for a bottom of the line rig.