The lock code is generally more simple and practical to use their key counterparts. Thanks to electronics, Master Lock makes the use of such products even easier. Gone are the unique combinations, limited and inconvenient to change. Here, this is from 4 to 12 positions based on four key codes (Up / Down / Left / Right), if need be associated with letters of the alphabet. This lock can handle a main code, code three "guests". A website associated offers free and secure storage of 1GB and the possibility of finding a code "master" of aid in case of loss of principal code. The instructions supplied - ESPECIALLY NOT astray - is very well written and describes a perfectly clear all the features of this product. This lock operates with a battery (CR2032) which should allow approximately 5 years of use. It is very difficult to change the battery when the padlock is locked. We must therefore ensure that the change from the first alert. From a mechanical point of view, this is massive and seems robust. As stated, it is restricted to indoor use.