Coin vibration motor, also known as shaftless or pancake vibrator motor.

These days miniature vibrating motors are used in a wide range of products, like tools, scanners, medical instruments, GPS, and control sticks. Vibrator motors are also the main actuators for haptic feedback which is an inexpensive way to increase a product's value, and differentiate it from compeition.

Can be affixed in place with a very strong permanent self-adhesive mounting system.

Voltage Range: DC 0.8 - 3 V
Max rated current: 80 mA 
Motor diameter: 8 mm
Motor thickness: 3.4 mm