Retail price: 8,800 yen (Purchased from the Stokke official website in March 2024. I've included a screenshot of the purchase as proof, if needed - see photo 4). Stokke YOYO car seat adapter. Allows you to attach compatible car seats to the YOYO stroller. I used this to attach a Cybex travel system car seat. There are some minor scratches (see photos 2 and 3), so please consider this a used item before purchasing. Compatible car seats that can be attached to the YOYO (quoted from the official website): These are the car seats compatible with the car seat adapter that fits the YOYO² frame: BeSafe iZi Go Modular X1 Cybex Aton Q Cybex Cloud T & Cybex Cloud T i-Size Cybex Cloud Z Cybex Cloud Z2 i-Size Bebe Confort/Maxi Cosi Pebble Pro Maxi Cosi Pebble 360 Pro These are the car seats compatible with the car seat adapter that fits the YOYO³ frame: YOYO car seat by BeSafe Cybex Aton Q Cybex Cloud Z Maxi Cosi Pebble 360 pro BeSafe iZi Go Modular X2 Cybex Aton S2 Cybex Cloud G Cybex Cloud T