The tube is capable of much more than producing a few handkerchiefs, and is described by Harold Rice as The Utility Tube for vanishing, producing and exchanging silks.(Silk Encyclopedia - Page 330).
It can also be used with items other than silks, and for several novel and off beat effects. 
Silk Blendos are more effective in the tube than in a Change Bag. because of the visual nature  You could also work it in reverse, pushing in a large multicolor silk, and having this "disintegrate" into several small solid color ones.
You get the mechanical tube with instructions. Tube measures 2.5? diameter, 6.5? High, resting on a base base 4?x4?. No silks or other accessories supplied.