This small empty squeezable plastic bottle by Colors for Earth is one of the cleverest I've come across. It holds an ounce of fluid and has two screw parts: 1) the red cap screws onto the bottle and 2) a tiny clear plastic tip screws onto the very top. When both of these are closed, the bottle has a good seal to protect the contents. Fill the bottle with your favorite liquid paint or paste, then screw on the red cap, unscrew the plastic tip, and you have an "undertip" with a fairly large hole that extends out beyond the cap so you can use it to fill in larger areas of paint or to draw thick lines. OR, purchase one of the Colors for Earth tips shown elsewhere on this page and gently screw that onto the cap to draw a variety of lines in paint or paste to suit your needs. If you like to paint and enjoy versatility, you'll love these bottles!