Style: CP360 (bore size 3.6 mm / Single Flange)SpinFit is a patented ear tip. SpinFit has an ergonomic concave design at the core to allow the ear tip to swivel, making it flexible to bend and twist to the contour of a person's ear canal. SpinFit ear tip is able to be inserted deeper into the ear canal, enabling less obstruction along the sound field dispersion path, which results in greater audio experience while providing maximum comfort.WHAT SIZE? The different size ear tips accommodate to different ear canals. Choosing the proper size is critical for a secure, comfortable, and quality result. If you?re unsure, medium size fits most users comfortably. WHICH MODEL? CP 240: core inner diameter is 4 mm (Double Flange) - deeper insertion - CP 240 w/ insert: core inner diameter is 3 mm CP 800: core inner diameter is 2 mm (Single Flange) CP 100: core inner diameter is 3.8 mm (Single Flange) CP 360: core inner diameter is 3.6 mm (Single Flange) -for True Wireless CP 145: core inner diameter is 4.5 mm (Single Flange) CP 155: core inner diameter is 5.5 mm (Single Flange) CP 360: core inner diameter is 3.6 mm (Single Flange) - for True Wireless COMPATIBILITY. Different models are designed with different core sizes to fit all major earphone brands.Please confirmearphone model / measurements before purchase!CP CP 360 fits models including: Powerbeats, Jabra, Sennheiser, Anker, Sony, B&O, Sol Republic, Pioneer, RHA, JVC, NuForce and most True Wireless earphones! (Do not fit Bose's & Erato's TWS) QUESTIONS? Visit SpinFit Website