A tassel for use in a covering for an architectural opening is provided with an opening in one end for receiving a flexible elongated member of the type used in operating such coverings and an opening of a different configuration in the opposite end for receiving a wand or similar rigid elongated member also used in operating coverings for architectural openings. An oil recovery system, in particular for collecting oil from a water surface, includes a plurality of such oil boom skimmer members connected in series to form an oil spill recovery boom apparatus. At least first and second layers of insulating material are applied over the active area. The barrier covers an opening of the mount and retracts into the concave portion of the mount by being pressed by the image taking lens unit when the image taking lens unit is attached to the image taking main unit.