I recently bought the Weboost 4G RV. I won't be able to test it until my next trip in September. But in my office, it showed a gain of 24dB. The RV version is the same as the M version, but has a directional antenna. A directional antenna will give you better gain than an omni-directional that comes with the M. There is even a website that will give you the direction of the closest tower for your carrier.
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