The transparent housing for cold water allows to visually control the replacement filter condition. The fittings made of brass withstand hydraulic shocks in water main. Pre-filter removes rust, sand and other mechanical sediment, which is useful to ensure longer life of drinking water filters, improve shower and bath experience and protect home appliances. ½'' brass fittings prevents excessive strain in the case-fitting connection unlike pre-filters with plastic threaded sockets. It makes the whole construction much more durable. For a high quality of water purification we recommend using Aquaphor pre-filter cartridges that fit the 10'' Slim Line standard.