In May 2019, I contacted Simon at PitPat to ask if I would be too small (1.4kg) for the PitPat activity tracker and Simon said "The honest answer is that only you can really judge. We always say that if a dog is big enough to wear a collar, they can wear a PitPat. It certainly won’t be too heavy, but you’ll need to judge whether [you] will be happy with it all the time, or you might find that you can put the PitPat on when [you] go for walks and take it off at home." and kindly gave me a discount off the product.
I didn't need to track my activity until we signed up for Cancer Research Woof All Over Cancer in March 2020 where hundreds of my friends all over the UK are walking between 5k-10k steps every single day! We signed up (thankfully the discount still worked) and I am going to start using PitPat for every walk in March!
As it happens, I have started piling on a few pounds over Winter so it would be good to see if I lose any weight this month!
Update: The good news is its not too big and I don't even notice I am wearing it on a walk!