These dumbbells of 320 lbs weight disassembled and fell apart while a guy tried bench weightlifting. These adjustable dumbbells with 160 lbs of weight on each side started slipping as soon as the guy got in position. The weight slipped off one side of the dumbbell on his right arm, causing the dumbbell to be unbalanced and tip the other way, which caused the weights on the other side to fall down. All this weight pulled him off the bench and threw him onto the ground.