ITEM NAME:KY-031 3Pin Percussion Knocking Knock Sensor Module for Arduino DIY Starter Product Description Description: KY-031 3 Pin Percussion Knocking Knock Sensor Module for Arduino DIY Starter Kits Specification: Application: loudspeaker Power voltage: 1.9-3.6V Size: 18x15x10mm/0.71x0.59x0.39'' Packaging weight: 3g Note: 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! 2. Please allow 1-3mm measuring deviation due to manual measurement. Included: 1 x Knock Sensor Module.Included: 1 x Knock Sensor Module. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. If item is defective after 3 months, you can still send it back to us.