The standard size fits most clock cases ( 3-6mm panels) with 17mm shaft and 9mm thread specifications DIYer enthusiasts and repair technicians appreciate the easy installation Crafted with through precisions injections molding, this light yet sturdy movement resists damage better than metal alternatives This 17mm shaft swing movement features chimes striking, accurate hourly melodies for great time management Ideal for offices or classrooms, the quartzs mechanism ensures consistent Enjoy classical melodies from the built in music box, creating a refined ambiances in living rooms or studies The soothings chimes transform every hours into a moment of auditory delight without disrupting your activities Specially designed quiet movement minimizes operational noise, maintaining peaceful environments for bedrooms or quiet spaces The noise reduced mechanism promotes better sleep during nighttime hours