Perfect for Summit X3, can be installed inside the seat or remove the seat first!
Baby Jogger Summit X3 To to Attach Bassinet and Capsule - YouTube
The New Baby Gear We Added to Our Collection for Two Kids: Baby Jogger Summit X3 Double Jogging Stroller and Graco 4Ever Extend2Fit 4-in-1 Car Seat - Glitter, Inc.
Baby Jogger Summit X3 Double Jogging Stroller, Black and Gray - Walmart.com
Summit X3 Baby Jogger With Bassinet for Sale in San Francisco, CA - OfferUp