3/8-inch side-entry toilet cistern filling valve with a brass union connection, designed as a replacement part for various Grohe cisterns and for universal application in high- and low-level tanks. It is widely available online and from local plumbing suppliers. 
Key Features and Specifications
Connection: Features a 3/8" BSP threaded brass union connection for a secure, leak-free, side-entry installation.
Compatibility: This is a universal application valve suitable for low and high-level cisterns made of plastic, ceramic, or cast iron. It is also known as a direct replacement for built-in Grohe toilets and works well with the compatible model 37092000.
Performance: Requires a minimum recommended static pressure of 0.2 bar and includes an adjustable float to customize the water level.
Material and Finish: The main body is durable plastic, and it features a "StarLight Chrome" finish.
Installation/Maintenance: Reviewers note it is generally easy to install, though it can be fiddly in compact spaces. It has a removable cover and flow restrictor for straightforward maintenance.