i use Dakine lock
main reason i advocate using a lock
some guy doesnt mistakenly (intentional or not) take your board
if they have pliers, wire cutters, etc
they intended to go to the snows to steal boards
not much you can do about that
essentially the lock goes around the heel loop of the binding with a fixed object...normally racks at rest area
two models
3/4 digit combination or key lock
key is self explanatory
3 digit combination uses 3 digits to lock
betters instructions come with the lock
basically, push down on the head to set the lock number
pull up to set
don't set something half heartedly and forget the lock or else thats 15 bucks down the drain