18″ Parachute 6 line. LOC/Precision Parachutes use a low porosity rip-stop nylon at 1.9 ounces. It is a urethane coated, calendared rip-stop that allows almost NO air through. Yes, it is a bit heavier. But! It will have a slower decent rate than a lighter, un-coated material in a same sized parachute!