I thought these antennas like this one work way better. It is a dual band like the little magnet one above.
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Antenna theory and design is complex. Gain is often misunderstood. High gain has trade offs in the “shape” of the signal. In many mobile situations a low gain antenna may outperform a high gain antenna. If you want to antenna-match for a specific booster application, go to a site like the Repeater Store and check out the possibilities. They sell a wide variety of boosters with specialized inside/outside antennas for specific purposes.
Cellular Antennas for DAS, Repeaters, Boosters and Amplifiers