Westone AM Pro20, Universal In-ear Handset, SLED technology for the isolation of ambient noise, For live application and band practice, Dual drivers, Passive two-way crossover, Frequency response: 20 - 18,000 Hz, Maximum level (at 1KHz): 119 dB SPL, Impedance (at 1 KHz): 27 Ohm, Ergonomic earphones for high comfort, Replaceable cable