Tests on three early streamer emission (ESE) terminals, manufactured by different firms, were carried out. The main measure criterion was the breakdown voltage of the air gap consisted of the high voltage electrode (rod or plate) and a grounded ESE terminal. Additionally, the time to breakdown was estimated from the oscillograms. The breakdown voltage was measured at standard switching impulses or under lightning impulses of both polarities or under AC voltage. The used distance ranged from 5 cm up to 4 m and voltage magnitude from 30 kV up to 2.5 MV. Except only one ESE terminal showing an advantage at an air gap of a few centimetres under AC voltage, these careful measurements show that the air gaps with ESE terminals have the same breakdown voltages as the air gaps with Franklin rods. Therefore, the large protection zone of ESE terminals, as claimed by their manufactures, is practically impossible.