This is a great product, as long as you realise the limitation of its size: the interior dimensions of the U-lock are approx. 150x40mm. I use it mounted on my cycle down-tube, securing the rear wheel. A separate, larger U-lock and/or cable is needed to secure the bike to something immovable. That said, this is a solid bit of kit, with a loud alarm. I find it very reassuring to have an audible alarm to deter tampering.