For use in applying/storing liquid dye concentrate when painting yarn. I did a little more homework on bottle sources and have found a bottle I like a little more than the others I carry. These are HDPE plastic, more rigid as compared to my other squeeze bottles which are LDPE plastic and softer. I added a yorker cap with a large red tip which will be easier to keep track of. While all the bottles I have are good and work well in dyeing, these will likely last longer.