The Button Head Coupler attaches to EZ-3P or EZ-4 injectors to allow grout to flow through. *Injector not included.
Avanti's Resin Injection Accessory Guide
The EZ-3P injector has 0.28" diameter port and 5/8" outside diameter which allows for greater flow at high pressures.
The EZ-4 injector has a steel ball one-way valve, 0.28" diameter port and 5/8" outside diameter. The disposal composite plastic material is designed with button head coupler connection.