Strong and durable - injection molded of high-Impact, chemically resistant polypropylene * Ergonomically designed for comfort and quality * Seat bumpers are "Molded-In" for extra strength and durability, never need replacing * Ultra-Violet Protection Molded into each seat to prevent color fading * Simple to install - only requires a screwdriver, adjustable hinges for perfect fit, corrosion proof, self-aligning hardware