•Invisible design: F50D2 is an in-ear hearing aid that uses precision acoustic components to provide a sophisticated design that is invisible to wear •Advanced sound processing: Adopts 16-channel WDRC digital chip for precise sound processing •Excellent sound quality: Enjoy excellent sound quality with 16-channel low-level extension, maximum output tone control and 64-band equalizer •Intelligent noise management: Achieve clear conversations with intelligent background noise suppression and adaptive feedback management •Convenient adjustment: Easily adjust the volume and switch programs with the multi-function button and volume adjustment key •Rechargeable function: Powered by a lithium battery, it provides long use time and a fast 2.5-hour charging time to ensure uninterrupted hearing support Specifications: •90dB output sound pressure level: maximum: •50dB saturated output sound pressure level: maximum: 30±5dB / average: 28±5dB •Frequency range (Hz): 250-5000Hz •Harmonic distortion: 500Hz: 5 percent / 800Hz: 5 percent / 1600Hz: 5 percent •Equivalent input noise: •Working time: 24 hours •Working voltage: DC 3.0-4.2V •Charging time: 2.5 hours •Battery capacity: 450mAh for charging box, 35mAh for hearing aid Package included: •2 x Hearing Amplifier •1 x Charging Case •1 x Charging Cable •6 x Earplugs •1 x Cleaning Brush •1 x English User Manual