Almost every AC motor that is connected to the speed controller will usually cause a hum/hum from the motor. Sticking one of these between the ESC and the motor will reduce it significantly. Most are larger (and more efficient), but for a small motor, they're small enough to fit in the back of a deep single box behind the speed controller.
Cordless DEWALT DCD701F2 Xtreme Brushless Drill
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π§ Dewalt DCD791D2 Compact Li-Ion Brushless Drill
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Xiaomi Wowstick 1F+ cordless screwdriver black
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For locksmith, repair and precision work Stels Tool set, 1/2", 1/4", CrV, 82-pcs plastic case, Stels, 82-pcs, silver
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