Dear Mr. D,
I have two quick questions for you.
#1 Where can you find good eye-glasses for dummies?
#2 What sources do you know of that sell the water glass within another water glass for vent demonstrations?
* * * * *
From Mr. D:
#1 For greatest visibility of eye movement, I prefer that there be no lens in the eyeglasses figures wear. For eyeglasses for figures, I just buy cheap kids' (or adult) sunglasses and remove the dark lens.
#2 Magic suppliers have the "Magic Milk Tumbler" - at least that is where I used to purchase them. I purchased from D. Robbins & Co. but they do have minimums: http://www.ezmagicrobbins.com/catalog/productDetails.aspx?ProductID=19650