Yes these are quite inexpensive to make as we have very high cycling rates on this particular size of keg. The plastic will be tinted dark brown just like a beer bottle. We might also use a metallic colourant that blocks even more light but it also makes it hard to see the liquid level. We can make them block 100% of light if you guys want but this means you cant see through at all? What do you guys prefer to see through a little or to have 100% light block and not see how much is in the keg? Keen to get your response on this one guys?
I think you'll have different answers from different people, but I personally would prefer the 100% light block version, as I weigh with scales as I fill anyway.