Item Type: Open-Gear Guitar Tuners Gears_x000D_ Material: Iron_x000D_ Gear Ratio: 1:15_x000D_ The gear is in the form of a hex hole. Please pay attention to this problem when purchasing. Thank you for your cooperation. 1The gear ratio is 1:15, with 15 teeth more convenient to use, and the product has high quality and good experience. 2The product is very suitable for the replacement of the head gear of the tuning knob of guitar, bass and ukulele instruments. 3The gear is in the form of a hex hole. and it has exquisite workmanship, excellent texture, glossy exterior for your use. 4The open?gear guitar tuners has small size, make it more lightweight and portable, and easy to use and carry. 5Good?quality basic tuners for guitar and more, easy to install on and also very sturdy.12 x Open?GearGuitarTuners Gears