These are Saarinen Executive Swivel Arm Chairs, originally designed by Eero Saarinen in 1957.  The chairs are comprised of a 5 star steel base with a manual lift adjustment and a plastic padded seat that is upholstered in black leather. The listed price includes on chair and there are more than 12 available to purchase.

Introduced in 1950, the chair brought elegance and comfort to the then dreary world of executive seating. With its timeless shape, graceful curves and balanced proportions, the Saarinen Executive Chair is now just as likely to be found in dining rooms as in offices. 

These pieces show very minor wear and overall are in very good condition. Please see photos.