25mm High Fidelity dome tweeter with glass fibre reinforced plastic chassis. The unit features high efficiency and smooth, extended response. Its aluminium diaphragm with critically designed shape and thickness behaves like a piston throughout the audible frequency range, resulting in good dispersion above 10 kHz. A fine mesh grid protects the diaphragm, and supports a phase plate which compensates for a slight axial roll off towards 20 kHz. The specially designed soft surround allows excellent mechanical linearity. A damped hole in the pole piece and a tuned chamber behind the magnet result in a low resonance frequency.