i know I need the rough in box but is the valve included with this trim kit?A. Yes, The Grohe 19 867 comes with the control module. This, along with the 35 026 box will make up a fully functioning unit.
Can two separate shower functions be operated simultaneously?A.
Unfortunately, no. The Grohe 19 867 can only run one function at a time. There are no Grohe combo handles that operate that way, you will have to purchase a separate diverter such as a Grohe 19 181.