abstract
assembling
base
connection
construction
coupling
detail
dirty
durable
electric
electrical
electricity
energetics
energy
equipment
fastener
fixture
fragments
gray
grungy
industrial
industry
infrastructure
installation
iron
magnesium
mechanical
metal
metalwork
noncorrosive
nut
object
outdoor
parts
pins
plate
pole
post
pylon
red
reliable
renovation
rivets
screw
steel
structure
support