Theft deterrent. Brass With Nickel plated Cover Corrosion Resistant. 1/4" Connection - 35 Chrome A/C Locking Caps Per Box. A/C Valve Cap ECWB This refrigerant locking cap is an essential accessory to ensure your air conditioning system operates smoothly. With this cap, you can have peace of mind knowing that it is tamper-proof, providing added security. It is a must-have for anyone who wants to protect their A/C unit from unauthorized access or tampering. By securely locking the refrigerant cap, you can prevent any potential damage or disruption to your cooling system. This product will help you sleep soundly, knowing that your A/C is well-protected and functioning optimally. Don't compromise on the safety and performance of your A/C unit; invest in this reliable refrigerant locking cap today.