Outside features: shells made of the Bam Hightech technique : a triple-ply structure made of high performance materials (ABS, Airex foam, another type of ABS); outstanding protection and ultralight weight; two comfortable neoprene anti-slip backpack straps with security screw hooks; two combination locks; side handle; subway handle; male/female airtight seal; anti-slip and anti-wear rubber patches on the bottom outer shell.