E61 Group Head Restrictor Jet, 0.6mm Orifice This is the small brass restrictor jet that controls water flow rate through an E61-style group head, sold individually. The 0.6 mm orifice is a specific flow-rate spec, so swapping to a different size will change your shot times even if everything else about your machine is dialed in. SPECIFICATIONS M6 x 0.75 mm thread, 0.6 mm orifice COMPATIBILITY Fits: E61-style group heads using an M6 x 0.75mm restrictor jet INSTALLATION Quick swap for a technician with a small wrench and access inside the group head, no gaskets or special tools involved. PRO TIPS If your shots are pulling noticeably faster than they used to with no change in grind or dose, a worn or eroded jet orifice, not just your grinder, is worth ruling out; mineral-laden water erodes the orifice edges over years and effectively enlarges it, speeding up flow.