Used to connect the manometer to the pump head.
Fits to K: HD 6/16-4 MX, HD 6/16-4 M Plus, HD 7/18-4M, HD 7/18-4M PLUS, HD 7/18-4MX, HD 9/19 M, HD 9/19 M Plus, HD 9/20-4M, HD 9/20-4M Plus.