We have child-resistant caps of various sizes that comply with Code of Federal Regulations (CFR) Title 16, Part 1700. Sometimes people will ask for caps for a certain size container but caps do not work that way. A 2oz container could be short and squat and have a wide diameter while another 2oz container could be tall and skinny and have a very small diameter (we have both kinds). As you might have guessed, you need to know the diameter of the cap you are looking for. So you will typically see the diameter of the neck opening listed on all of our bottles, jars, and caps. Caps and closures are measured using two numbers like 53-400. The first number is the distance in millimeters of outer thread to outer thread when looking at the top of the container. The second number is a reference to the thread design. Just pair your bottle or jar with the same cap diameter and you'll have a match. Of course, don't forget that you should always get samples first to make sure everything matches up correctly and will work properly with your product.