The bottles are good quality plastic with three indications of ml levels. Each bottle comes with a luer-lock cap (connector cap) where to insert the needle tips, a cap for this lock, plus the 4 different needle tips sizes (3 items for each size).
I use the connector cap as a controlling dispenser to use small quantities of fluid acrylic paint; this allows me to do this without leakage and without blocking the pout. This saves me product as many of the flow acrylics I own squirt out of the tub on their own, wasting product and even staining my hands and clothes. So these bottles are awesome to store those paints, dispense them properly and prevent spillage. Filling them with paint is also great because the only thing you have to do is unscrew the lock cap and them screw it back.
One of the main issues with other needle bottles I've used in the past is that the acrylic paint/ink tends to dry inside the needle, clog it, and eventually ruin the whole cap system, which ends either in wasting the bottle or having to pay for new caps. However, these needle bottles' locking system is great. These needles are easy to "plug"/"unplug" and easy to clean, so you only plug them when needed.
Good value for money, as well. I've already bought two sets.
