Coolant mixers mix coolant concentrate with water and dispense it to a coolant sump, tank, or reservoir for use. They automatically deliver a specific ratio of coolant concentrate to water, which saves time and improves consistency when preparing multiple batches of coolant compared to preparing them by hand. Coolant mixer lockout valves attach to coolant mixers to prevent unauthorized changes to the mixers' settings. They have a lockout cap, padlock, and key.