In 2018, the Sega Shop has created this white Knuckles theme water bottle.
It's ceramic-coated stainless steel with a plastic screw cap top & karabener so you can hang it on a belt loop or bag. It's also 21 dollars which is a little pricey for a simple bottle like this.
It's also boring. There's not any actual design going on here much. They just took a Knuckles stock line art & put him on there with red ink. It's also just the face & his chest marking. It's neoclassic, and not an over-used piece of art but....the whole thing just comes across as really plain. Everything doesn't need to be highly busy or plastered in logos but there's a difference between a subtle item and something that's low-effort, too. It's good that it's a Knuckles solo item, excellent for Knuckles fans...and the art is good, but for the price it is, one might expect a little more.