Have you looked this up online? It's a whole, expensive system that produces that product.
http://www.sugarveil.com/icing_dispenser/index.htm
Yes, you can just buy the icing and use a bag to pipe. The system just makes it a little easier, in my opinion. I use it for most all my lettering and whenever I need dots -- no more points on dots. You can check out the cakes in my gallery -- I've used it a lot, so to me it was worth the money especially because I don't have a whole lot of experience with freehand piping.
Duplicate post, please see also:
http://forum.cakecentral.com/cake-decorating-ftopict-545963.html
HTH
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