The smooth black polypropylene disc top closures are made with a slight indent in the plastic top, which is designed to have a light amount of pressure applied to it in order to expose the orifice where the product can be dispensed. The 20/410 disc top caps have .270" orifices, the 24/410 caps have .308" orifices, the 24/415 caps have .310" orifices and the 28/410 caps have .325" orifices. Applying light pressure to the open end of the cap will also easily close the cap. The black polypropylene disc top closures are a great choice for dispensing products such as shampoos, conditioners, lotions, and soaps.