Tribeca Genuine Wood Aviator Headphones for Kindle Fire HD, Maple Certified "Made for Kindle" accessory (Kindle Fire and HD Models) Sound chamber crafted from genuine, natural wood creates an unparalleled acoustic experience Speaker size 40mm with 18Hz-22Hz frequency response; Sensitivity 110+/-3dB at 1kHz, 1mW Output power is 30mW rated with 50mW max