This is a Trijicon Cover, model AC31023.
This Scopecoat fits all MRO(R) optics. The Scopecoat is constructed of the highest quality neoprene laminated with nylon. Its simple design safeguards the scope from dings and scratches" dust" dirt" and moisture. Neoprene has a 5% moisture absorbency which takes moisture (condensation and sweating) away from the scope and helps protect it. The nylon shields against the elements. Simply stretch both ends over your scope. The recommended fit is either "relaxed same length" or slightly stretched.
Features:
Safeguards scope from damage
Has moisture absorbency