Brass Tune Up Kit for Gaggia，Replacement for IMS Precision Shower Screen，Brass Shower Holder, Silicone Gasket, Stainless Steel Screws.

Definitely descale and back flush (I like using PBW cleanser for my back flush). Most people will probably also recommend the Gaggia descaler, but pretty much any descaler/acid works. Also, this is a nice little upgrade for cheap https://a.co/d/00sPfDvU