Apparently sized for the Space Shuttle Rotational Hand Controller (RHC).
Similar to the type of dust boot known to be used on the RHC (shown at left in the photos below), but actual use unknown.
Obtained as surplus from NASA.
Tags associated with the dust boot include NASA JSC part number SDD39111429, and catalog number 190005P8.
NOTE: In photos below, dust boot on left is a known Space Shuttle RHC dust boot. It is NOT INCLUDED with the purchase of the dust boot at right in the photos.