Two speakers 16mm, oval. Impedance 8 ohms, 1-2W, with common sound chamber. When Choosing the speaker of the type of decoder used is crucial. Depending on the decoder, different speakers are suitable: LokSound V4. 0 and LokSound micro V4. 0 decoders require the new speakers with 4 ohms impedance. With the previous 100 Ohm speakers you will hear hardly anything.