I bought these for colouring epoxy in inlays I create on my CNC machine. A couple things to be aware of: 1. There isn't quite the variety you'd expect. The selection is dominated by reds (6 or 7). There are only 2 browns (coffee and caramel), one orange and one yellow. 2. With the cap off, the drip nozzle is only friction fit into the bottle. Always check that the nozzle is seated before inverting the bottle. 3. My personal preference would be for greater opacity in the colours.
All that said, they're easy to use, do the job, and are a decent value for the money.