Emmaljunga/Britax Baby-safe plus SHR II adapter...
Bugaboo Donkey Mono adapter for Britax Römer® car seats | Bugaboo
Amazon.com: Britax Infant Car Seat Stroller Adapter for Nuna, Cybex and Maxi Cosi Car Seats, Compatible with Britax Single Strollers Only, 2 Count (Pack of 1) : Baby