For those wanting a very inexpensive and lightweight PA system, this mini-amp will work with the H1a hydrophone to create a small group listening environment. These are often used by whale-watch groups operating out of inflatables or kayaks. Even some large tour vessels with high-power PA systems use them. The naturalist simply holds her microphone up the the speaker to play cetacean sounds though the PA. Don't let the toy-like appearance fool you. These are great for their size and cost--sounding quite good and playing fairly loudly. Use the Honeytone amp's headphone jack output at times when you want to listen more critically. The headphone jack can also be connected to the AUX input of a marine stereo system--using the speaker as a cheap hydrophone preamp.
1-watt amplifier with 4-inch speaker. Only 5 inches square by about 2-1/2 inches deep and weighs only one pound. Uses one 9-Volt battery, included. Not waterproof.
See and hear a demonstration of this speaker, used with the H1a, as recorded on video at YouTube here.