Mei Hatsume won a design contest, and her prize was watching the U.A. faculty hobble themselves with her invention. Compacted into a size that straps to a limb, each weight piles on roughly half its wearer's body mass, bleeding away speed and stamina.
These weights come from Mei Hatsume, whose design took first place in a competition held to source them. Extreme compaction is the trick that makes them practical, since it shrinks them to something a person can strap around an arm or a leg without difficulty.
Roughly half of the wearer's own body weight is what a single unit adds. The effect is deliberately punishing: whoever wears them moves slower and tires faster.
U.A.'s teachers put them on for the First Term Final Exam, handicapping themselves so their students had a fighting chance in the matchups.

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The High Density Weights are a piece of support equipment invented by Mei Hatsume, compacted small enough to strap around a wearer's arm or leg after her design won a competition held to source them.
Each High Density Weight adds roughly half of the wearer's own body weight, deliberately punishing them by slowing their movement and speeding up fatigue.
U.A.'s faculty strapped on High Density Weights for the First Term Final Exam to handicap themselves, giving their students a fighting chance in the matchups.
The U.A. staff who wore High Density Weights for the exam included All Might, Eraser Head, Midnight, Cementoss, Snipe, Power Loader, Present Mic, Thirteen, and Ectoplasm.
Mei Hatsume invented the High Density Weights, winning first place in a design contest held to source the equipment for U.A.'s exam.
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