Ordering Ring from amazon - but not everything

Being and amazon prime member, and since ring is owned by amazon, I bought all my ring stuff on amazon. But like many people, I found the ring sensor magnets to be too large for my windows. So I was looking around on amazon for smaller magnets. Fortunately, before I ordered some I wandered over to the ring site. There you can by small ring magnets, which I did and which work great - they are really small. Anyway, my point is, I am surprised that there are things for sale on the ring site that are not on amazon. Makes no sense, and I bet a lot of people have no clue as to the availability of those items. I would think there would be a complete ring store on amazon. Most odd.