I needed convenient tuner but did not want to carry one with me. I found this clip-on unit in Guitar Center, I believe it's made by Korg. I clip it directly to the bridge from the E string side and just leave it there. As with every other addition to the Stagg, it fits into the bag with it, and is not bothering me at all. It is powered by internal a coin cell and with occasional use will last years. Small detail, but added convenience and confidence of correct tuning you can check at any moment without powering the bass or connecting external amp - the tuner detects vibration of the bridge and does not need audible sound to work.