With swimming ear plugs, the goal is to keep water out, but allow sound in. These Alpine ear plugs definitely do the job. A special filter system prevents water from getting inside the ear, but still allows the wearer to hear most speech and other noise. To ensure an optimum fit, the eartip on these reusable earplugs can be cut to size. The unique filter system blocks water from entering the ear and allows a good level of external noise and speech to be heard. The eartip can be cut to size for optimum fit.