It's made of metal material, which is wear resistance and practical for the time use. The metronome pendulum can move up and down, and the scale corresponding to the position of the pendulum indicates the number of per minute corresponding to the pendulum. The replacement piano metronome sliding block is easy to install and requires no additional tools. Changing the position of the pendulum block can change its vibration period, all a good pendulum block is very important. Simple and convenient installation without any screws, just need a minutes to install. Suitable for most metronomes. Weight:13.4g/2pcs Colour:silver Material:Metal Size:17.7 x 18.7mm Package Contents: 2 x Metronome Slider Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.