The main body fabric is made of Cordura Ballistic® Hollofil AIR with 2 strands of 420d Hollofill Air (66 nylon hollow yarn) and 2 strands of 420d Hollofill AIR are also combined with 2 strands of 420d and 1680d x 840d. In addition to the durability of CORDURA® fabric that is resistant to wear and tear, the hollow thread has been made lighter, and the attachment is made of DP X-pac for strength and accents. The included key chain is made of vegetable tanned leather with a luminous paint applied to the glowing leather that collects sunlight during the day and glows in dark places. This product has been made to be lightweight with a heavy appearance and minimal efforts of leather and metal parts. ABOUT [CORDURA BALLISTIC® Hollofil AIR™ ] CORDURA BALLISTIC® - Hollofil AIR is a 420d Hollofil Air (66 Nylon Hollow Yarn) twine with two strands of 420d Hollofil Air (1680d x 840d fabric. in the future. A new brand made with hollow yarn to reduce weight due to the durability of CORDURA® fabric that is resistant to wear and tear. Ballistic hollow yarn is lightweight yet stronger and more durable.