If you want to change the tone, you must change the vibration frequency, and you need to change the vibration length by hand, thus changing the frequency.
The vibrating object of this instrument is a rubber band, which is similar to a string, so it belongs to a stringed instrument.
Timbre refers to the quality and characteristics of an object's sound, which is determined by its material.
So the answer is:
(1) The strength of pulling the rubber band by hand;
Change the position of the left hand to change the length of the vibrating rubber band.
(2) stringed instruments, vocal materials.