We understand that you need containers to package and ship your products. That is why plastic containers come in all sort of shapes, sizes, and color of almost any imaginable need.
Plastic has the advantage that it is break-resistant, light-weight, and low-cost. You are not going have to worry about it breaking during transport as you would for glass containers. You also don't have to worry about your customer dropping it. Imagine if someone dropped a glass jar of baby powder that broke upon impact. If you ever had to clean up such a mess up, you will understand why baby powder comes in plastic containers.
Plastics are very easily molded. Hence, the variety of plastic bottles are more diverse than glass bottles. Plastic bottle manufacturers can produce square bottles, rectangle bottles, oval bottles, and even hexagonal bottles. The most common shape is the round bottle that we usually think of.
Bottles can be threaded for a screw-on cap. Or the plastic bottle can be non-threaded to accommodate a friction-fitted cap. There are also plastic bottles with "hang-up caps" for packaging of small lightweight products. These are friction fitted caps consisting of a tab with an hole for hanging. For an example, picture a plastic container bottle containing screws hanging on a shelf.
Tables of stock sizes are readily available to aid you in your selection of bottles of various inner and outer diameters with various wall thicknesses.
We also understand that you may have very specific needs. Your needs may be so specific that you might not be able to find a stock size that is perfect. Not to worry, there are many bottle manufacturers that will custom mold your plastic bottles per your specifications. You will often work directly with one of their engineers who is familiar with the whole manufacturing process. They can even color-match your bottle, similar to how you would color-match an existing paint color when painting your house.