The Koochi Upstart 0+car seat ISOFIX base is ultra-convenient. If youve got ISOFIX anchor points in your car (and nowadays most cars do), then just pop your Upstart 0+ car seat on and off your in-situ ISOFIX base. ISOFIX is minimal faff - just simplicity with a satisfying click that lets you know its fastened securely. Winner of no. Compatible with upstart 0+ car seat. ISOFIX compatible or use with 5 point. Compatible with the koochi upstart 0+ car seat (sold separately) isofix system for optimum security easy to install complies with ece r44/04. 4 year (when registering within 28 days). Manufacturers 4 year (when registering within 28 days) guarantee.