What part of a grease gun connects to the Zerk fitting of a bearing housing?

The coupler is the part of a grease gun that connects directly to the Zerk fitting of a bearing housing. This component is specifically designed to create a secure and airtight seal around the Zerk fitting, ensuring that grease can be effectively pumped into the bearing without leaking. The coupler typically features a spring-loaded mechanism that holds it in place on the fitting, allowing for more controlled and efficient lubrication.

Using the coupler correctly is essential for maintenance tasks, as it facilitates the precise application of grease, which helps prolong the life of the bearing and ensure smooth operation. The other parts of the grease gun, such as the valve, barrel, and handle, serve different functions that are not specifically related to the direct connection with the Zerk fitting.