2.5mm 4-pole headphone jack. I purchased this at e-earphone, but I'm selling it because I no longer plan to make a conversion cable. Therefore, although it is new, please understand that it has been in someone's possession once, and that there may be some slight variations due to product specifications before purchasing. 【High-Quality Sound】 NOBUNAGA Labs' headphone jack adapter uses gold-plated materials, providing clear sound without compromising sound quality. 【Compact Design】 The small and lightweight design is convenient to carry and can be easily connected to smartphones and tablets. 【Compatibility】 Compatible with many devices and can be used with various audio equipment. - Brand: NOBUNAGA Labs - Model Name: NLP-PRO-TPFEN - Price: ¥1320 - Material: Gold-plated - Color: Black - Type: Headphone jack adapter Thank you for viewing.