I really like the clean simplicity of the design for this Mini Koo Non-Electric Speaker. Essentially it’s just a wooden amplifier but a beautifully crafted one at that. It’s made from walnut and fits all iPhone sizes to increase the volume of your music without cords or electricity. Very elegant.
LG G Pad 7.0 Case - Poetic LG G Pad 7.0 Case [Turtle Skin Series] - [Corner/Bumper Protection] [Grip] [Sound-Amplification] Protective Silicone Case for LG G Pad 7.0 Black (3 Year Manufacturer Warranty From Poetic)
Fundamentals of Distributed Amplification (Artech House Antennas and Propagation Library) (Artech House Microwave Library (Hardcover))