Polk Audio DB522 DB+ Series 5.25" Coaxial Speakers with Marine Certification, Black MAV NUTRITION They also have thick walls

They also have thick walls to increase the service life under difficult outdoor conditions

Get the workout you need without sacrificing space

accessory pockets and a water resistant valuables pocket

Fast Focus System

BRASS MATERIAL: Lead-free Brass construction with superior rust-resistant finish

Polk Audio DB522 DB+ Series 5.25" Coaxial Speakers with Marine Certification, Black MAV NUTRITION They also have thick wallsBrand: Polk Audio Color: Black Features: High performance audio upgrade that delivers signature quality sound that goes beyond OEM factory systems Marine certified with IP55 rating (water and dirt resistant) and tested for salt fog, UV and humidity Polypropylene and UV tolerant cone with waterproof inner and outer surrounds Simple drop in installation for any vehicle including cars, boats, ATVs you name it Cut out Diameter 4. 76" Bottom Mount 2. 01"