I use two KryptoLok Kryptonite Series 2 New York and I am very satisfied but the keys are similar, I wanted to buy another brand to find my way on my keychain "bicycles". This Zefal Ktraz with cable is a French brand but the quality seems well within Kryptonite yet not much more expensive. The finish is lighter with a thinner coating of metal, a temperamental lock and also a less clear lock for which to grope. If Zefal suffers a bit from the comparison Kryptonite in absolute remains correct and well used. It comes with 3 small keys and a code card which can control a new key "in case." The only area in which it is superior is fixing to the bicycle frame. Indeed, in the Kryptonite device is complex to install whereas here 2 screws (4 are provided according to the thickness of the frame) are used to grip the frame with the two parts of the clip.