Fumei VHF 130-174MHz 30W Duplexer for Radio Repeater with Preseted Low Frequency 134MHz & High Frequency 139MHz & N Female connectors

I operate a lab which tunes, repairs, and services consumer and commercial grade duplexers. I have been contacted by clients complaining that they purchased a set of these exact model duplexers but could not get them to tune or work properly at the typical 600 KHz frequency split used for Amateur Radio repeaters. They were asking if they could sent them to me for repair and tuning. Unfortunately, the seller neglects to mention in the product details that these duplexers WILL NOT WORK with a high side to low side (or transmitter-to-receiver) separation less than 5 MHz. The same seller DID somewhat vaguely allude to that fact in an earlier listing here on Amazon for this same duplexer. Bottom line: if you're a "ham radio" person looking for duplexers for a 2-Meter band repeater, these WILL NOT WORK for that application.