The C&C 355mm-square (14") mesh grid panels are ideal for small animal enclosures such as guinea pigs, but affixing water bottles and the like to these grids can be a bit awkward if you want something more secure than the usual piece of twisted tie wire holding the top of the bottle.
These adapter plates hook onto the grid wires (not the thicker edges) with a positive snap action and allow the use of a 'Pet One' brand small water bottle but other brand bottles might also work (feel free to modify the OpenSCAD source provided here for your bottle). They can be clipped and unclipped in seconds, making it easier to refill your piggies water with a minimum of fuss.
There are two options:
You can print the general-purpose hook plate and new C-clip design, or a hook plate if you weant to use the C-clip that came with the bottle.
The new design uses a small self-tapping machine screw to hold the pieces together. This is so you can print the hook plate on its side edge for maximum strength in the layers. Similarly with the C clip, print on its bottom edge so the layers are built up as C's.
The C clip has small holes in its outer ends to allow a piece of tie wire (such as from a bread bag) if your bottle is a bit loose. The hook plate also has holes for tie wires if you require it permanently fixed to the grid panel.
If you print the hook plate for the original C-clip, be very careful when fitting and turning the clip 90 degrees as they are quite fragile and can break at the pivot point. To mitigate this somewhat, use an Exacto #11 knife to make sure the two "ramps" in the centre hole has clean sharp bevels, and test rotation a bit at a time until it smoothly turns 90 degrees and locks on the small pips on the inner (animal facing) surface.
I printed these from PLA, 100% infill. ABS would also be a good choice.
In the photos you can see both versions being used side by side, our piggies are just fine using them.