Specification Frequency Response-20~20 000HZ Impedance-16 OHMS Sensitivity-112DB SPL 1MW nbsp; Feature 1.It can be used on driving easily to put the micro-phone around neck like a necklace. 2. The removing part of cell-phone is distinguished from the previous and it looks like an accessory. 3.The both side are the same so it looks fine externally. Caution on use 1.Please avoid high temperature high humidity and a direct ray of light while keeping. 2.Please do not give a shock and do not pull the cord.