This is advertised on Lazada which is sort of like ebay.
The description translated by Google says
• Designed specifically for pre-sensitive sensitive protection end from high levels of RF effect from nearby signal transmitting;
• The SDR receiving Antenna is very close to antenna transmission, or supporting antenna or Failure systems that cause a high RF water input receiving antenna input, may cause SDR receiver to freeze.
• Measurable: receive antenna is 10 meters from antenna transmission, and transmit function is 1000W. The SDR receiver can work normally.
• Only receive protected front head, 50 or 75 Ohm compatible; preamplifiers and radio protection from excessive RF.
• Has all the great features, and shares an identical Form factor to ensure compatibility with the surrounding options.
I have no idea and don’t want to spend ₫447,000 to find out.