ANTENNA

SMA-F to SMA-F Adapter
Excellent fit on the B1-Plus.
DIAMOND SMAJ-SMAJ Low Profile Black SMA-Female to SMA-Female Adapter

Antenna Thread Length Variability
“Huge” variability in the base-to-end lengths of the Chinese-style antennas that fit the RFinder, Anytone, Baofeng, etc., radios. The thread length doesn't seem to be well standardized. Some fit, some are too short and don't connect, and some are too long and damage the radio's antenna connector. Once you have an adapter that works, you no longer have to think about it. Get a single adapter that demonstrably works, like a SMA-to-BNC a SMAJ-SMAJ adapter to use Japanese-style SMA-M connectors).