In order for a Wifi stick to connect to a router and thus to the Internet, it needs an antenna. It makes a big difference whether the antenna is inside or outside the housing. Often the antenna is not visible and is located inside the device. These are usually very small and inexpensive antennas, but they are also much weaker.
If the antenna is attached to the outside of the housing, the antenna can pick up the signal much better and thus offers a better connection. These models are usually a little more expensive. In return, however, the antenna can be replaced more easily in order to achieve a greater range.
The following table compares internal and external antennas based on different criteria: