WHD LST 50 GMP UP, 100V-speaker controller (via transformer), 50 W, for in-wall mounting, ür Gira LST 100 GI UP, LST 100 GI UP -R, LST 100 ME UP, LST 100 ME UP -R, LST 100 PE UP, LST 100 PE UP -R, note: very linear speaker controller because of transformer technology