Abstract: A down-hole assembly used to locate an existing window in a main cased well bore and guide equipment through the window and into a lateral well bore after removal of a whip stock. The assembly includes a running tool with a convex section detachably connected to a concave section of a guide member. The running tool includes a window locator that locates the window. The guide member includes an inclined or wedge shaped portion for guiding tools or equipment through the window and into the lateral well bore so that remedial work can be carried out.