i just got a fancy light bike, and i'd hate to add too many pounds to the frame by strapping on a several pound u-lock. does anyone know of ultralight locks that can only be defeated with grinders?

what about this thing?

https://tigrlock.com

seems to be the current winner. there's a video showing them grinding through it, and it takes them a good second (if they made it seem like you couldn't, you'd know it's a scam). is kind of expensive, but one pound or less. i'd like them to offer a guarantee like kryponite, but i don't see one mentioned on their website.

anyone have any negative comments about this thing or know something better?

thanks!