Review on 📡 High-Gain External Magnetic Loaded Coil Antenna (6.5~8 dBi) for Cisco, Cradlepoint, Netgear, Novatel, Pepwave, MoFi, Digi, Sierra & Other 3G/4G/LTE Routers & Modems with SMA Connectors - Pack of 2 by Atheendra Wroblewski

Looks reasonably well built and is very good value for money for Consumer grade ANT. The product is delivered in consumer packaging. They use the same (3mm?) base as these inexpensive antennas. The magazine bottoms have good grip and can support their own weight, even when upside down. This is the DEFAULT POLARITY and will not work with most consumer wireless networks (see vendor photo to see the small pin in the center of the connector). It would be very helpful if the manufacturer provided a proper datasheet showing SWR and gain versus frequency (please extend this to 3GHz). Not sure if they are intended for outdoor use like in a car. I've attached some SWR scans I ran on a very basic NanoVNA v2. The SWR scan shows an interesting 30MHz harmonic and I'm not sure if this is a test artifact or caused by the nature of the ANT boot.