Different ear pieces
Noise Braker® Standards are just that, standard. They are mass produced ear tips with the Noise Braker® filter inserted in the body. The soft accordion style tip has multiple flanges that seal the ear from sound and keep it in the ear. This leaves only one way for sound to enter the ear, through the Noise Braker®, thus letting the Noise Braker® do it's job. The effectiveness of Noise Braker® Standards relies on how well the ear is sealed. This can change depending on the size and shape of a persons ear. For example, if a person has large ear canals, the plug will not seal properly and sound will get around the plug and to the ear drum, thus rendering it ineffective. But because they are mass produced, they are lower in cost.
Custom Noise Brakers®, on the other hand, are made from an impression taken from a persons ear. As such, they completely seal off the ear from any sound not entering through the Noise Braker® filter. The ear mold is made, a hole is drilled into it, and the filter is placed in the hole. Because each plug is made for an individual person, they offer better protection than Noise Braker® Standards, but at an increased cost.