It can be adapted to work with any size plumbing within reason, but it comes with everything for an installation on standard 1/2" plumbing typical for a kitchen sink.
See this link to look at the installation instructions:
http://www.waterfilters.net/PDF/Cull...gan_Manual.pdf
It's the manual for the SY-2650 which is exactly the same as the US-1500.
Thank you,
WaterFilters.NET