This is a Color Parrot 1.0 white balance measurement tool. (It is a predecessor to the ColorRight white balance measurement tool.) It is placed in front of a digital camera lens to make a custom white balance measurement with the camera. It is essentially a measurement diffuser. It includes the original screw-top case.
The unit is equipped with 82 mm filter threads. It however can be used on any lens of that size or smaller, and is in any case ordinarily just held in front of the lens while the measurement is being taken.
The manufacturer asserts that useful white balance emasurements can be made with the camera, equipped with the device, at the location where it will be for the actual shot, aimed at the actual subject.
Caveat: we do not endorse the theory, or lack of it, behind that mode of operation. But many users supposedly report useful results in many cases with the device used that way.
The manufacturer also says that, if desired, the unit can be used in the classical way, in which the camera (with the device in place) is placed at the subject location and the ambient light that will fall on the subject is allowed to fall on the device.
Caveat: the device does not exhibit the "cosine" angular directivity pattern generally considered desirable from a theoretical standpoint for this type of measurement. The manufacturer explicitly tells us (in somwhat vague terms) that the pattern is "norrower" than that, supposedly an advantage in the first technique I mention above.
In this unit, the overall "filter" diameter is about 76.5 mm; all but a central circular area of diameter about 37.5 mm has a second translucent layer of unknown properties. The manufacturer suggests that this is in the interest of attaining a "narrow" angular acceptance pattern.
Caveat: We know of no theoretical basis by which this would substantially narrow the angular acceptance pattern of the device (nor do we know of any theoretical reason why doing so would be advantageous).
The unit is in like-new condition. Curiously, the case opens in the clockwise direction.
The model identification seen in the photo was applied by me.
The unit will ship to the US by USPS First Class Mail.