The JBL ES20 is a bookshelf speaker that features a two-way, bass-reflex design. It comes equipped with a 5-inch woofer and a 0.75-inch titanium-laminate dome tweeter, offering a frequency response range of 60Hz to 40kHz. The speaker is designed to handle up to 125 watts of power. Its dimensions are compact, making it suitable for small to medium-sized rooms. The ES20 is often praised for its clear treble and strong bass performance relative to its size.