Rockville MS40B 4-Inch Marine Speakers | 200W Peak, IP56 Waterproof, UV-Resistant

Rockville MS40B: Compact Marine Speakers with Big-Bold Sound

The Rockville MS40B pair brings vivid, high-fidelity sound to boats, ATVs, motorcycles, and outdoor setups. With a 200W peak (50W RMS) and a wide 122Hz–20kHz frequency range, these 4-inch speakers deliver clear vocals, bright highs, and well-rounded midrange to keep your music feeling alive on the water or on the trail.

Built for rugged environments, the MS40B features an IP56 waterproof rating and anti-UV ABS plastic, helping resist salt, freshwater, rust, and sun exposure. The compact design fits tight installations while still delivering impactful sound that can be enjoyed dockside, in open air, or along winding roads.

Why the MS40B Stands Out

• SUPERIOR SOUND QUALITY: 200W peak (50W RMS) with a 122Hz–20kHz range for music and vocals on the water.
• MARINE-READY DURABILITY: IP56 protection against salt, freshwater, and rust; anti-UV plastic for long-lasting color and strength.
• COMPACT, EASY INSTALL: 4-inch speakers with a 3.66-inch cutout and pre-installed mounting screws that simplify on-vehicle mounting.
• STURDY CONSTRUCTION: Injection-molded polypropylene cones, aluminum voice coils, and 3.5 oz Y30 ferrite magnets for reliable performance.
• OUTDOOR-READY VERSATILITY: Designed for marine use and adaptable for cars, ATVs, or motorcycles in harsh conditions.

What You’ll Hear and How You’ll Use It

Expect clear, balanced sound with capable highs and responsive mids, even when wind, waves, or engine noise is present. The 85dB sensitivity helps the MS40B perform well at moderate listening levels without excessive distortion, making it a practical upgrade for onboard playlists, outdoor gatherings, or road-trip calm with a trusted soundtrack.

Real-life scenarios where these speakers shine include a sunset cruise with friends, a dockside brunch, or a dusty trail ride where you still want robust audio. Their compact footprint and screw-in mounting approach make installation economical and straightforward, so you can enjoy music sooner without major modifications.

Specifications at a Glance

• Peak power: 200W (50W RMS)
• Frequency response: 122Hz – 20kHz
• Impedance: 4 ohms
• Speaker size: 4 inches; cutout diameter: 3.66 inches
• Durability: IP56 waterproof, anti-UV ABS plastic
• Construction: Polypropylene cone, aluminum voice coil, 3.5 oz ferrite magnets
• Sensitivity: 85dB

With the MS40B, you’re not promising guaranteed results—you're exploring the possibilities of clearer, more reliable sound in rugged, outdoor settings. The combination of compact design, strong build, and versatile use makes these speakers a noteworthy option for water and outdoor enthusiasts who value sound quality without sacrificing durability.