FPPI® aluminum caps are forged from T6061 aluminum alloy then hard anodized to improve corrosion-resistance and surface strength. Each cap is accurately machined and will provide years of service. Our pin lug design is compatible with all fire service pin lug hydrant wrenches. Protects male threads and discourages the introduction of debris into the hydrant or valve. Suitable for fire protection or industrial use. Aluminum's low value compared to brass also discourages theft.