The RF-353 (a.k.a. AM-7224) is a one-tube (3CX1500A7) linear amplifier that was designed to be used in combination with the RF-350K 100Watt transceiver. It was sometime in 2003/2004 that this fantastic piece of equipment was offered on eBay. As I soon found out, it was offered there by a retired engineer formerly employed by the Harris corporation. To make a long story short: we made a deal and BAX helped me getting three of this magnificent amplifiers in Holland.
The amplifier covers the 1.6 Mc - 30 Mc frequency range, and tunes automatically (in combination with the aforementioned RF-350K).
This Amp is really bullet-proof too: about every voltage, current and temperature present is constantly being monitored. If anything is wrong the control-unit s huts the Amp down before any harm is done.
The output power of 1 kWatt is reached with about 35 Watts drive. Beyond that drive-power, the Amp signals the RF-350K to reduce power-output.
Tried out in combination with a Drake-4C at PA0GMW's QTH (my next-door neighbour), the Amp easily ran 1.5kWatt key-down.
One other big plus of this Amp is its serviceability. Thru a very  modular design ATU, power deck, control boards and every other PCB is easily accessible and removable/exchangeable for service.

AM-7224 1 kWatt LPA on top of accompanying PP-7913 PSU

LPA set to "Automatic tuning"

Top cover removed: ATU control unit PCB cleary visible

Triple-PI filter at LPA's output