Make & Break Relay It is also known as SPST (Single-Pole, Single-Throw). There are 4 pins (or terminals) on the body with one high current circuit and contact. The contact is opened or closed depending on whether the relay is at rest or energized. 1. ● If the contact is closed when the relay is at rest, the relay is called Normally Closed (NC). 2. ● If the contact opens when the relay is stationary, the relay is called Normally Open (NO). These relays are the more common type. Changeover Relay It is also known as SPDT (single-pole, double-throw). There are 5 pins (or terminals) on the body, there are two contacts connected to a common terminal. The relays have two circuits, one is closed when the relay is at rest, and the other is closed when the relay is energized.☑ Avoid direct sunlight and maintain normal temperature, humidity, and pressure as below: 1. ● Temperature: 10 ℃ ~ 35 ℃ 2. ● Humidity: 5 ~ 85% RH 3. ● Air pressure: 86 ~ 106kpa. ☑ Regularly check the products in stock and try to avoid the relay storage time being too long. ☑ The relay shall be stored and installed in a clean environment. Please use a dust cover or plastic encapsulated relay in the environment with dust pollution.