This 1/4 inch quick-connect straight union is the popular for use with connecting a water ionizer hoses together. It will work for any hosing that is 1/4" outer-dimension of the hose.
It's called a "union" because it allows you to join two pieces of 1/4 inch hosing together.
![Ring Clamp [For 3/8 Inch Hosing]](https://cdn11.bigcommerce.com/s-bz401t/images/stencil/500x659/products/707/668/ring-clamp1__35717.1703638051.jpg?c=2 "Ring Clamp [For 3/8 Inch Hosing]")