Kitty - I was told it was the Valco toddler seat that fits it. I asked in a couple of baby shops and they both said this, but also qualified it by saying they would never recommend using a toddler seat that was not specifically designed for that particular pram - obviously needing to protect themselves in case you buy one and something goes wrong. MB are apparently working on their own toddler seat, but haven't managed to come up with a design they are happy with in terms of safety etc.