The Mackie CR4X 4" Woofer Creative Reference Multimedia Monitors (Pair) are a compact and portable solution for providing audio playback in home and studio environments. They're designed for multimedia work such as mixing music or post-production sound design. The pair consists of one passive speaker and one Class-AB powered speaker that connect with an included stereo cable. The monitors use 4" polypropylene-coated woofers with a rear port tube for the low end, and 0. 75" silk dome tweeters for the highs to deliver a frequency response of 60 Hz to 20 kHz with a maximum SPL of 100 dB. A switch allows you to select whether the powered speaker will function as the left or right speaker. This is helpful when having to position the speakers near power outlets or when deciding which side is preferable for the volume knob. A front-panel, LED power-ring illuminated on/off switch and volume knob allows you to control level. A dedicated front-panel headphone jack defeats the main speaker output and can be used to expand the system's monitoring versatility. A front-panel 3. 5mm stereo input and included 3. 5mm to 3. 5mm cable allows you to connect your smartphone or other mobile device directly to the monitors. Other equipment such as audio interfaces, CD players, or mixers, can be connected to the rear panel's 1/4" TRS, 3. 5mm TRS, or RCA inputs.