Dyneema® Arm Protection is Cool! One of the most distinguishing Dyneema® characteristics is its cool-to-touch property. Dyneema® fibers inherent ability to dissipate body heat and pass moisture from inside of the sleeve to the outside, results in longer wear time which promotes greater protection. The 9318D7T is a 7 gauge Dyneema® Diamond Technology sleeve with a thumb hole. It is 18 inches in length.