access
blockade
blocked
chain
clasp
closed
corrosion
crime
duty
fence
ferrous
gate
heavy
inaccessible
industrial
iron
keep
key
keyhole
links
lock
metal
metallic
old
padlock
post
prevent
prevention
private
property
protect
protection
rusty
safe
safety
sealed
secure
security
shiny
shut
silver
steel
stop
strength
strong
thick
trespassers
wire