The unit has only five LEDs, which makes the process of fine-tuning difficult. The lights changed when we moved the unit around, but not the aerial. Still, we got a decent picture when two of the LEDs were showing, and the unit is simple to use, despite its instructions, which are confusing. It comes with adaptors and a battery, which attaches externally.
The Practical Motorhome Maplin Aerial Signal Strength Meter review