IFeng 2 Pin Flexible Acoustic Tube PTT MIC Earpiece Earphone for Two Way Radio Kenwood TH235A TK3160 Baofeng BF530 BF777S Space of two-pin: 11mm The plastic ear bud fits snugly to your ear canal Two-pin standard diameter: Ear 3.5mm stereo (top pin). Mic 2.5mm stereo (bottom pin) Excellent for use in police, military, nightclubs, bars, paintball, security, restaurants, hotels, bouncer, warehouses and noisy environments Low-profile, flexible, transparent acoustic tube transmits sound in high quality; the transparent tube would be hardly noticed by others around you