This is a Tiffany & Co. sterling pen and pencil set.
The set advertises "Applied Materials". The pen writes in blue ink and the pencil uses 0.5 leads.
The pieces measure about 5" long and have the "T" clips, and are engraved Tiffany & Co.
They are in pre-owned condition in a felt bag. The pen needs a new filler, and the pencil has no lead but there are extra leads under the cap.