If you have replaced your lock barrel recently it is more than likely that the replacement was bagged as a Lucas replacement (Lowe & Fletcher). The keys that come with these late replacements originally say Lucas on one side and have grooves (milling) on one side only. (cross section image is the hole key goes into) Key-LF10 is sent as a blank replacement for you to have cut by your local locksmith. For those buying replacement barrel/keys sets we can cut to match if ordered at the same time (please let us know you would like this done)
Note tell you locksmith to line up the tip of this key with your existing when cutting NOT the shoulder as he would normally do.