This is a filter under the neck shower arm diverter device which can be used to get a point of 1/2" from the sink mixer or wall shower. 
Both opposite sides of this shower arm adapter have a 3/4" thread. you can easily attach a bidet sprayer, Muslim shower, hand shower, water filter, and automatic washing machine after connecting this device to a wall shower or kitchen mixer. You attach a machine bush of 1/2"*1' mm thread with this adaptor device as well. you don't need to call a Plumber, you can do it yourself. Just attach the neck adaptor with your mixer (The mixer thread should be 3/4"). Then attach any kind of product having a 1/2" thread with this diverter.