I have recently purchased a Schneider APO HM 150mm lens. It came with two accessories which I don't recognize. One is a translucent sleeve which Schneider's website shows as being mounted around the rear barrel (placing it inside the enlarger lens cone). The other accessory is an aluminum sleeve that looks a lot like some kind of lens shade but I suspect has something to do with mounting the lens in a particular enlarger. I will try to attach a picture for clarification. Can anyone tell me what the translucent plastic sleeve is for and how it is used and even what the other aluminum sleeve is.