Koss IL100 interlocking in-ear headphones features a truly original design coupled with a unique material to form a perfect harmony. The interlocking in-ear headphones utilizes an ingenious patented design for easy on-the-go storage without sacrificing richly delivered audio delivered through performance tuned 9 mm drivers. The frame of the interlocking in-ear headphones is constructed from highly polished metal and surrounded by flexible, soft-touch material. This innovative material doubles as a soundproofing coat, intended to deaden any unwanted distractions, that allows the listener's focus to remain on the crystal clean highs and crisp lows - while staying inside the music they love. The interlocking design allows the two in-ear headphones to easily nestle together for simple, tangle-free storage. With its durable metal structure the IL100 in-ear headphones will eliminate the stress of trying to undo the impossible knots that always seem to form when storing in-ear headphones or earbuds. Koss has created the perfect harmony between form and function, so that all you have to worry about is the music.