These have literally changed my life! If you use Angelus 4oz paint,I HIGHLY recommend getting these. The paint that dries up around the lid of the paint bottles (especially in the grooves) can often create tiny clumps in the paint which can cause your coats of paint to be less smooth and if you use an airbrush, these little clumps can create a lot of headaches for you. Straining your paints is always a good idea, but you can lose a lot of paint over time. I find that using these twist top caps helps with pouring your paint, saving time, and prevents a lot of the dried clumps of paint, ultimately saving you more paint. This is probably one of my favorite non-paint items in this website!