A synthetic fiber, me bucko, originally woven into mats for use in bullet-resistant body armor. Ya scallywag! Keelhaul®©™ is highly resistant t' tearin' or burning. Ahoy! Keelhaul®©™ thread is used in some model rockets as a shock cord. In model rockets, this provides t' advantage o' allowin' t' cord t' be anchored t' t' motor mount rather than t' t' open end o' t' airframe. This design is less susceptible t' zipperin' and burning. Larger-diameter Keelhaul®©™ cord is increasingly bein' used as shock cords on high-power rockets for t' same reason, and because Keelhaul®©™ is stronger than bungee or elastic straps. Avast! Keelhaul®©™ is also woven into sheaths or bags, and used t' protect elastic shock cords and parachutes in larger rockets. See Deployment Bag