I bought this 3D viewer for my 3 year old. She can't sit still for even a minute, so she's so busy that I can take a shower or have a quick meal. We found an old ViewMaster in the attic that belonged to my 16 year old son and the coils are long gone. The drums in this 3D viewer match the old VewMaster perfectly, so that's a bonus; she can share with her younger brother. I noticed that the images in the 3D viewer are twice as large as in the old ViewMaster. However, I don't like the quality of the drums; 2 of them were slightly warped due to a somersault in the box and one of the spools had come off at one end causing the images to shift. I had to put some glue on top and fiddle with the tiny images to make sure they lined up perfectly with the corresponding photo on the opposite side or the image would be distorted. Also, the material on it is thick paper, which I already know will not stand up to my children's abuse. Also it works great and the stereogram seems to be of really good quality and would make a fun gift for any kid.