Glide Foam’s unique multi-curved stem rotates for a custom fit inside each ear canal. With its unique curved stem design, you simply push & twist for Glide to angle its way to find your fit. Glide Foam features a high NRR 30dB which is among the highest independent ratings for a no roll style plug. All Moldex hearing protection is independently tested to ANSI S3.19-1974 by Michael & Associates, Inc., State College, PA