This economical shower water filter uses a patented copper-zinc alloy, that is the most effective way to remove chlorine in high temperature shower water. With this technology, this filter has been shown to effectively remove 95+% of this damaging chlorine,. It lasts about a year (for 2 people) which is about 2 to 3 times longer than other filters. This filter can also be useful to remove sulfur, plus iron and other heavy metals. It also helps control the mold and mildew in your shower. A unique feature of this shower filter is the "Dial-A-Date" reminder ring. When you install it, you simply rotate the blue calendar ring to line up with the current month. It will remind you when a year has passed to ensure you are getting the best quality water possible. It installs quickly, with no tools, on any standard shower arm. Simply unscrew your showerhead from the shower arm, attach your showerhead to the end of the filter, and install the filter on the shower arm. Must be used with a 2.5 gpm of water(or less) showerhead for best results (Showerhead not included).
Filter is 4" long, 3" in diameter. 
Overall dimensions: 6.7" tall X 3.75" diameter
Manufacturer of filter media: KDF Fluid Treatment
Technical questions: 800-437-2745, info@kdfft.com