"A certified-safe, ultra-cheap scooter whose performance will likely disappoint anyone over 150 lbs."
The '21-mile range' is a theoretical maximum calculated under ideal, unrealistic conditions. In daily use, expect a functional range of 5-8 miles before the battery needs recharging.
This is justifiable for someone needing the absolute cheapest, lightest scooter for very short, flat, dry trips, like from a parking lot to a building. The UL safety certification offers a baseline of electrical safety absent in many competitors at this price.
Anyone weighing over 180 lbs, living in an area with hills, or needing to travel more than a few miles at a time should look elsewhere. The performance claims will not hold up for most adults, and its long-term durability is a significant gamble.