Hellobee Boards

I had this exact issue, my B-Agile is also 6 years old, and I scoured the interwebs for months while pregnant with #3 to try to find that darn carseat adapater! I think because the adapter click part was recalled (at least mine was) they probably just stopped making the adapter frame. I did exactly as @avivoca and just bought a Snap N Go to use with the carseat until he's big enough to go in the stroller by himself.

I used the Chicco Keyfit carseat and B-Agile stroller with an adapter I bought on amazon. Strangely though I can't seem to find it in my order search from the year I would have bought it. I remember it was around $50. I can take a look, but I don't think I have it anymore. I will check and let you know though.