Check the listing for details. Grainger Locking Thermostat Cover 3TZ57A. Condition: New. Listed at 6.99 USD. Keep your thermostat safe and secure with this locking thermostat cover from Grainger. Designed for use with Grainger 3TZ57A models, this cover is perfect for environments where tampering or unauthorized adjustments are a concern. With a durable construction and easy installation, this cover is a must-have for any business or industrial setting. Protect your HVAC & Refrigeration system with this Grainger locking thermostat cover. The cover is designed to fit Grainger 3TZ57A models and features a thermostat lock for added security. This product is perfect for those in the business and industrial sector who need to keep their systems safe from tampering or adjustments. The cover is made from durable materials and is easy to install, making it a convenient and practical solution for anyone looking to protect their system.