Supergirl arrives back her place after a long night out on patrol and she is drained both mentally and physically. When she sees a box on the table she just assumes that Clark left it for her since he was the only one with a key to her appartment.
When she opens the box inside is a copy of her supergirl outfit only slightly altered the body suit had leggings that ran all the way to her feet and the top came all the way to the base her face. It was made of some material that she had never felt before
though it felt like rubber. The note that came with it said "Saw this and thought of you. S"