Final answer:
Adjustable blade clippers, often used for fade cutting, have a lever that allows the adjustment of the stationary blade to change the closeness of the cut, operating on a principle similar to scissors, which are a double-lever simple machine.
Step-by-step explanation:
The type of clippers that have levers to adjust the stationary blade close to the cutting blade for fade cutting are typically known as adjustable blade clippers. These clippers have a side lever that allows the barber or stylist to change the closeness of the cut without changing blades.
Scissors, mentioned in the references you provided, operate on a similar principle as they are a double-lever system, which means they work on the concept of levers, one of the types of simple machines discussed in physics. The lever on adjustable blade clippers is a crucial feature for precision cutting, especially when creating gradients or fades in hairstyles.