TAILONZ PNEUMATIC25mm bore 150mm stroke air cylinder double action with Y-connection and 2 pcs 6mm fitting MAL25x150

Q: Can this be used to pass water through it instead of air?

Seals and lube are designed for air. I don't think it would work too long if you used water.

Q: Can you adjust the stroke on these cylinders?

No. They have an internal detent. The end is threaded so you can make a small adjustment at the coupling.

Q: Question to the seller: Does this include the mounting brackets shown in the photo? if not, where can they be purchased?

It does not include the mounting bracket. Not sure where to buy one sized correctly. I mounted my 25mm by the hole in the back(top). for my application I wanted it to be able to pivot slightly. A bracket shouldn't be too hard to make. This is a great cylinder. I went back and bought the 100mm for another project.