This product is a speaker-dependent voice recognition module. It supports up to 80 voice commands in all. Max 7 voice commands could work at the same time. Any sound could be trained as . Users need to train the module first before let it recognizing any voice . On V3, voice commands are stored in one large group like a library. Any 7 voice commands in the library could be into recognizer. It means 7 commands are effective at the same time. voltage: 4.5-5.5V digital interface: UART interface and GPIO 5V TTL level analog interface: 3.5mm mono microphone interface and microphone pin interface recognition accuracy: 99% (perfect environment) Colour:Orange+black Material: pcb Size:3.1 x 5cm Microphone head in two styles, Not accepting designation Package Contents: 3 x Voice Recognition Module 3 x Microphone 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.