This is a Leupold Lens Protector known as the Alumina, model 59055.
Designed for Leupold scopes built after 2004" Alumina(R) Flip-Back(TM) lens covers feature powerful neodymium magnets to hold them securely closed and the triple O-ring seals provide maximum protection from the elements. Constructed out of durable 6061-T6 aircraft grade aluminum" they are precisely machined to allow for quick and easy operation" and a low-profile position" when open" make these Flip-Back lens covers stand above the rest. The round objective and ocular models can be rotated so they can open in any direction.
Features:
Aluminum construction
Precisely machined