How big is too big for a health-related product to carry around?

I’m doing a little survey to better understand how people feel about carrying products around on their person/body. The product is a heart wellness device that is about the size and shape of a golf ball but with some rubber portions so it’s gripp-able and easy to hold. It’s something you could maybe put in one of the pockets of your cargo pants, purse, gym bag, or on a keychain. Because it isn’t flat, it can be easily pocketed in dress pants or jeans. I mean you could but there would be a bulge. From a retail, consumer, ergonomic standpoint, in terms of size, I think it’s most similar to a cell phone or maybe a small flashlight. Can you think of any other objects this size that people carry around? If it was something that kept you healthier, how reluctant do you think you’d be to buy it and carry it with you if it was less easy to pocket? In other words, if it was something you’d have to put on a keychain attached to your keys, bag, or beltloop; or carry in a purse or bag, but it kept you healthier, how reluctant would you be to purchase it?