I do not regret the purchase, the lamp makes very light, has not focused state a good sized beam and focusing its payment to a reasonable range. With the service I am very satisfied. The button is located at the rear end of the lamp. Touch not to him, the lamp is running in Turbo mode as long as you hold it. With one-time snap the lamp will turn on 50% power at a second press to 100%. The Turbo Mode is also available in two modes. Time users are likely to find improvements, but enough for me the lamp for even casual use more than. It is the best lamp that I've ever had. Can you only recommend.