I recently bought Grohe Eurosmart monobloc taps for washbasin and bidet, but had difficulty finding suitable service valves to fit the 3/8" tap connectors on the flexible connectors on the Grohe monoblocs.
Eventually I found 1/2" to 3/8" reducing nipple in chrome to connect to a common 15mm x 1/2" service valve, but better I found 1/2" X 3/8" Threaded Chromed Water Valve Connector which fits nicely into a 15mm x 1/2" female elbow.
Eventually I found 1/2" to 3/8" reducing nipple in chrome to connect to a common 15mm x 1/2" service valve, but better I found 1/2" X 3/8" Threaded Chromed Water Valve Connector which fits nicely into a 15mm x 1/2" female elbow.