I bought this last year after reading reviews from overseas. It has a high review score on overseas earphone sites, and the sound quality is very good. I have many earphones, so I think the usage time is about 5 hours. I have lost the original case and will send it in a Panasonic case. I think the price is low. Thank you. Universal Fit IEM Aspire 4 64A-7365 Brand: 64 AUDIO Wearing style: Both ears, integrated left and right Earphone/Headphone type: Canal type Color: Black Wireless/Wired connection: Wired connection Earphone/Headphone features: Detachable cable Low-frequency range (Hz): 20.0 Hz High-frequency range (kHz): 18.0 kHz Sound pressure sensitivity (dB): 104.0 dB Drive system: Hybrid type