Copper washers have many uses as seals in plumbing, automotive applications, low-pressure hydraulics, pneumatics and pumps as well as a seal for drain plugs. They are well suited for use in outdoor architectural and building applications where there is exposure to the weather. Being a good conductor of electricity, copper washers are useful in electrical applications. The assortment contains 15 different metric sizes giving plenty of choice. Supplied in a handy plastic organiser box 210 x 110 x 30mm.