This is a triple-hybrid structure featuring a dynamic driver, a NOVA driver embedded in the nozzle, and a ceramic super tweeter. Specifications: Driver Configuration: 1 x 10mm Dynamic Driver, 1 x Nozzle-less Open Vent Armature Driver, 1 x Ceramic Super Tweeter Crossover: 3-way passive crossover Impedance: 20 Ohms @ 1KHz Sensitivity: 108dB SPL @ 1mW @ 1KHz I am selling these because I purchased different earphones and no longer use them. I was using them normally until then. Everything in the photos is included.