Coming mid-May, the new OnGuard Rock Solid U-Lock has a 2mm thick diamond ceramic coating that just bounces an angle grinder’s grinding disc off.
They say the coating is both slick and hard, which won’t let a standard grinding disc penetrate…it just slides. They demonstrated it for quite a while (and had a pile of used discs laying next to it from prior demos) and it showed absolutely no sign of having been cut…or even attempts at cutting it.
![closeup of grinder-proof coating on onguard rock solid u-lock](https://bikerumor.com/wp-content/uploads/2024/04/onguard-rock-solid-angle-grinder-proof-bike-u-lock-2-1536x1152.jpg)
![angle grinder trying to cut through the onguard rock solid u-lock](https://bikerumor.com/wp-content/uploads/2024/04/onguard-rock-solid-angle-grinder-proof-bike-u-lock-3-1536x1152.jpg)
It weighs in at 3lbs, comes with five keys, and includes up to $5,001 of insurance for your bike should someone manage to break it.
![packaging for onguard rock solid u-lock](https://bikerumor.com/wp-content/uploads/2024/04/onguard-rock-solid-angle-grinder-proof-bike-u-lock-5-1536x1152.jpg)
MSRP is $199.95.