This is a full-range 1BA earphone from Jomo Audio. Despite being a 1BA, it produces a sound with considerable depth. Operation confirmed. This is a defective item. There is a crack in the shell of the left earphone. Please refer to the images. The crack is relatively extensive, but I have been using it for commuting in this condition without any particular problems. However, it is advisable to handle it with care. Other than that, there are signs of use, scratches, and dirt. This is an auction for the main unit only, and the price has been reduced due to the above reasons. Please consider this after understanding the condition. The items I sell may include used items, so please understand that I cannot answer inquiries regarding usage period or frequency. Shipping included, this is a bargain item, so please refrain from price negotiations. Immediate purchase is welcome!