The whole lock is formed by a quenched high-carbon steel U-rod and a thickened alloy lock body. The appearance is as simple as a horseshoe, but it can bite the disc or spokes in an instant, forming a “steel threshold” visible to the naked eye.The lock core adopts a double-row marbles + serpentine key slot design, which is anti-prying, anti-pulling, and anti-opening; the surface is sprayed with environmentally friendly nano-paint, which is scratch-resistant and rust-proof, and does not fade in the sun and rain.It is intimate that a soft rubber sheath is embedded on the inside of the lock beam to avoid scratching the wheels or shock absorption; some models come with retractable mounting brackets, which become “car-mounted pendants” in seconds, so that they will no longer dangle during riding.It is not large in size och moderate in weight, and can be easily stuffed into the seat bucket or tail bag.A reliable U lock is the confidence of the knight when he leaves the car: stop, lock, and leave in three seconds.