black
bolt
conduit
connection
construction
control
cross
drain
equipment
factory
faucet
fitting
flow
fuel
gas
gasoline
gate
handle
icon
illustration
industrial
isolated
line
metal
metallic
natural
object
oil
part
pictogram
pipe
pipeline
piping
plumbing
pressure
red
set
sewerage
shape
silhouette
steel
system
tap
technical
technology
tube
valves
water
wheel