Polymeric now produces Blue/Yellow epoxy in tubes. This has a benefit of giving the sculptor more for less. However, since the mix ratio of blue/yellow is usually 1:1.5 there is a lot of blue waste. Polymeric does not sell the tubes individually so you can't buy a yellow tube by itself. Therefore the ribbon might be a better buy with less waste. There is a downside to the ribbon. The contact point between the yellow and blue ribbon cures over time and you still have some waste. Not as much as with the tubes.