This is a 5 piece print that can fit any medium to large sized dog.
I always forget to take poo bags on our walks, as well as emergency treats and a torch at this time of year. 
The 250ml can is just right for my dog (he's a 3 year old labrador) and he doesn't even notice it's round his neck. 
I got the idea from the keg that Saint Bernard's so often have around their necks! 

The clip that holds onto his collar is big enough to accomodate a 2cm wide collar snugly. The gap that you slide the collar through is about 9mm wide so very little chance of the collar coming out on its own. (we've tested it vigerously!)

Contruction:

• Print out all the pieces. (2 lids, 2 threads, 1 center piece)
• Test fit the pieces on the can
• Cut both ends off the can so that you can see all the way through!
• Superglue one thread onto the end of the can, wait for it to dry
• Superglue the centre piece in as clsoe to the centre of the can as you're able.
• Superglue the other thread piece to the remaining open end of the can.
• Screw on one lid, fill with your pups favourite treats, emergency supplies, then close up the end with the other lid.

DISCLAIMER:
Please make sure that your dogs collar is not too tight with this attached. We don't want anyone getting injured!