Meet the GEERXIN Outdoor 4G LTE Extender: an antenna that boosts your signal in your office, store, or warehouse. It comes with a RP-SMA Male connector and can be installed quickly. This is a directional solution, so it concentrates the signal in a single direction for better coverage.
The unit measures 8.27×8.27×0.98 inches. You can find more about it here.