Note
QST, Feb 1982, p .143.
From the ad:
This low profile unit produces 10W to 30W of output with drive from your 0.5W to 3W handheld. Turn it on with the convenient front panel controls including PWR LED and TX LED or slip the package under the seat out of sight and out of mind. Low insertion loss on receive and selectable power level design provides low VSWR to the transceiver. Use with any talkie from 0.5W to 3W for 10W to 30W output. Linear mode for SSB or FM (switch selected).