Lock nuts are designed to keep your faucet functioning properly by keeping the handle and cartridge working together appropriately. This model, our Danze Lock Nut (DA104267) is warrantied against defects for as long as you own it. And it Is made of solid brass, so you know you can depend on it to work smoothly and remain durable for years. Please be aware that this model is designed to work with a Danze single-handle faucet. At Danze we're proud of our corporate culture that demands excellence in our products and services-in design, in sales, in marketing, and in customer service.