Sold as 500/Box. Protects up to 33 dB. Contoured design is easier to insert, resists tendency to back out of ear canal. Bulk refills for leight source 400, leight source 500 earplug dispensers save time, waste and space. Length of use: Single use. Cord type: Uncorded. Bell shape delivers maximum in-ear comfort. Smooth, soil-resistant closed cell-foam skin prevents dirt build-up. Packaging type: Dispenser box. Uncorded earplugs. Meets ANSI S.3.19-1974. Bulk packed for use in a dispenser. 500 per box. Polyurethane foam enhances comfort, especially for long-term wear. Noise-reduction rate: 33 dB.