If it was a "Gun Vault" brand, IIRC, it accepts combinations of up to six entries (maybe more?) in length, and each entry in the combination can be a "Chord" of two, three, or all four buttons pressed together.
So you could have a combination of "4, 1+2, 1+3+4, 3, 1, 2+3" etc, and that is WAY more than 4 to the 4th power (256) combinations. That's more like the 12 Million that Torghn and Jorg mentioned...
With practice, it's no harder than a four single key entry.
But a big +1 to the discipline AND demystification issues above being the first line of defense.
So you could have a combination of "4, 1+2, 1+3+4, 3, 1, 2+3" etc, and that is WAY more than 4 to the 4th power (256) combinations. That's more like the 12 Million that Torghn and Jorg mentioned...
With practice, it's no harder than a four single key entry.
But a big +1 to the discipline AND demystification issues above being the first line of defense.