RentACoop Automatic Chicken Water Cup Waterer Kit for Poultry Review 

just use any pipe you think it might work

I know this is late but maybe will help others. That blue piece there looks to be normal or even food grade water hose. But you can also use PEX or even PVC pipe. Most times if you use a 23/64th (10mm) drill bit the hole with be just tight enough that you have to twist the threaded portion in. If you use a 3/8th drill nit it will tend to slip in and out almost to easily. But verify that with the instructions that come with the kit just in case there’s a change from what I got. My kit is a couple years old (i think) and was a left over hand-me-down from my sister where she had left over pieces.