rotated to a midpoint of the mixing control allowing for tap handles with a lifting movement to actuate the flow control in application to the invention by contrast the standard mixer cartridge is in the above mentioned 90 degree rotated orientation so that the two handles 20 a and 20 b are substantially horizontal when the spigot 62 is rotated to the midpoint of the mixing control and a left right movement of the handles actuates the flow control handles 20 a and 20 b are mechanically connected to spigot 62 via handle to spigot adapter 70 which comprises mutually opposite screw holes 71 a and 71 b 71 b not shown fixed to breech and mixer housing 50 by screws through screw holes such as 44 is a frame which extends to the opening cut into the partition 2 and comprises a frame border 40 shaped and sized to receive an edge of the partition bordering on the opening outer cover borders 10 a and 10 b are shaped to hook over the frame 40 at a top edge and attach via grub screws from below into grub screw receiving plates 42 and 43 on the frame sealing strips 51 and 52 are secured on an inside edge of frame border 40 so as to engage outer rotating part 30 at a top and bottom thereof when installed in the gap 14 a b defined in the cover sealing strips 51 and 52 help to provide resistance to water leakage from the shower recess side as do o ring seals.