The white version of the Sennheiser CX 3.00 Earphones offer an ultra compact ear canal coupling design with a dynamic transducer to deliver enhanced bass with a frequency response of 17 to 21,000 Hz, a THD of less than 0.5%, and a maximum SPL of 118 dB. The earphones feature a right angle 1/8" (3.5mm) plug for connecting to your mobile device. They come with a carrying case and a set of four (XS, S, M, L) ear adapters to accommodate ear canals of different sizes.