[waterfilters]

Most under sink systems slow down the flow rate too much to use with an existing sink faucet. The more contaminant reduction, the slower the flow rate of the water because the filter needs contact time to reduce the contaminants.

You could use the US-600 or the US-550 with the D-20 filter cartridge with a regular sink faucet. The D-20 reduces chlorine taste and odor. If you wanted a filter that reduced more contaminants such as the D-40, you would need a separate drinking water faucet.

http://www.waterfilters.net/culligan/undersink/housings/US-600.htm - This system comes with the D-20 filter cartridge.

http://www.waterfilters.net/culligan/undersink/housings/US-550.htm - You need to buy the D-20 filter cartridge separately.
http://www.waterfilters.net/culligan/undersink/replacement_filters/D-20.htm