The timer is very environmentally friendly: Without batteries, with only one Aufziehfeder it does its work. What is important for the function - it also works without pressure! I will water so that a hedge about Perlschlauch and 600 liters of rain vessel functioning properly. Is not surprising, since only a round rod with a hole is slowly rotated about the spring pressure. And since it does not come from China, they will probably keep long enough - let's see ... ;-)