The DiversiTech RSC-SLV-02 refrigerant locking caps by Sentry are a quick and easy way to comply with the IRC and IMC code requirement that all outdoor access ports on A/C and refrigerant equipment be tamper resistant. This cap is anodized in silver color and can be used on different types of refrigerants with a 1/4 in. access port. An O-ring seal is also pre-installed to prevent leaks