Below is a list of Plastic Crates manufacturers from Merrillville, Indiana. A plastic crate is a type of plastic container that is usually characterized by portability and an air-permeable design. They are generally light-weight in their construction to allow for ease of transportation. However, their lightness does not indicate compromised strength or durability.Most plastic crates are not air tight or waterproof and are used for short term storage or for shipping.