Nose trimmers generally work with tiny blades that rotate against a protective cover that protects the sensitive skin on the inside of your nose. Some trimmers have a spinning disk that moves the blades in a circle, and some have disks that move the blades to the left and right. Both are equally effective.
Some nose hair trimmers are corded or rechargeable (with USB cable or battery), but most trimmers are battery-operated or manual. Manual nose hair trimmers usually work with you by turning the handle with one hand while the other hand guides the tip or pressing the handle to create an oscillating effect.