The Boschmann XJ3-553B are 3-way coaxial full-range car speakers from the XJ3 Premium Line Series. These 5.25-inch (130mm) units deliver a 100W RMS continuous rating and a maximum power of 300W, operating with a recommended amplifier power of 5-100W per channel. They cover a frequency range from 50Hz to 23,000Hz with 90dB/w*m sensitivity and a nominal impedance of 4 Ohms. The internal construction utilizes a BM Audio self-stabilizing shock-absorbent magnet and high-frequency dome drivers with a silicon oxygen tetra-hedra core, while gold-plated terminals are used for the bass. Each 540g speaker has a mounting depth of 48mm, a magnet diameter of 87mm, and requires 9mm of clearance for the tweeter. The mounting points are 100mm x 140mm. The set comes in retail packaging with cardboard protection and includes two speakers, covers, and wire.