◆ 1. Newton's cradle is a device that demonstrates conservation of momentum and energy using a series of swinging spheres. ◆ 2. Newton's cradle features a plastic base, which is heavier and looks more elegant, our newton cradle use high quality nylon line which is strong enough to not be broken easily. ◆ 3. Suitable for children and adults, ideal for eliminating boring time and stress relief. ◆ 4. Use For: High quality Newton cradle 5 balls for office, science experimental classroom, science fair decoration, Perfect for Birthday, holiday, party, wedding anniversary, etc. Specifications ◆ Material: Plastic+ Steel + Nylon ◆ Size: 17 x 14.5 x 17cm ◆ Color: Black + Silver ◆ Weight: 450g Package Includes: ◆ 1 x Newton Pendulum Ball Tips ◆When you use this Newton stand, please move it along the horizontal line to avoid tangling the line. ◆If you are entangled with it, you can untie it with patience and time, and then repair it, just need some patience.