This is the red (red color) "XBA-C10" sealed inner-ear receiver from SONY. It is equipped with a high-sensitivity, high-resolution balanced armature driver unit (full range) developed by Sony, achieving clear, crisp vocals with a good extension. I purchased this new and kept it as a spare, but I will not be using it, so I am putting it up for sale. Although it is unused, please understand that it has been in someone's possession once, unlike a completely new item, before purchasing.