E61 Group Head Jet Filter A small stainless steel mesh filter that sits in the group head's water inlet jet, screening out scale and sediment before water reaches the shower screen and puck. Cheap insurance against a clogged or restricted group. SPECIFICATIONS Stainless steel mesh, 8.5 x 22 mm COMPATIBILITY Fits: E61-style group heads using an inlet jet filter of this size INSTALLATION A simple DIY task once the group is opened up, most techs replace this while they're already in the group for a shower screen or gasket service. PRO TIPS If you're seeing uneven extraction or uneven wetting of the puck despite a fresh shower screen and gasket, check this jet filter, it's upstream of the screen and easy to overlook, and a partially clogged one will choke and unevenly distribute flow before water even reaches the screen.