
Netgear AirCard 790

Netgear AirCard 790
How does this device work exactly? If I buy a sim card from Yallo, it provides me with 21mbts/8mbts. As with this card I can reach the 300mbts Max that this device gives me? How does it work? adding antennas to the product will improve or increase performance? what antennas are compatible with this product?