2x Chamberlain TX4UNI 4 channel universal transmitters, LiftMaster branded. I purchased these about 10years ago for £80 +VAT, used them for maybe 1yr/18 months then put them in a drawer where they've sat ever since. As I no longer have the garage I've no means of testing them, but they were brand new when I bought them and I had no issues when they were in use. You will need to satisfy yourself they are suitable for your application, and also how to program them.
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