The RSL-6x4 Multizone Remote Source Sellect & Volume Level Controller. Available in White and compatible with:
Z-Series (MK2, MK3, MK4), CX462, CX263, 46-120-Series, 46-50, 36-50.
 
4 x RSL-6 Volume & Source Remotes mounted on one 2-Gang UK Wall Plate.