Yoyo3 6+ Seat Base FabricThe Core of Your YOYOs Safety. Is your YOYO harness frayed, or has the internal seat base lost its tension? This is the genuine Stokke YOYO 6+ structural seat base. It is the vital component that supports your child's weight and provides the 5 point safety attachment. As an Authorised Workshop, we only install official Stokke Babyzen load tested bases. This is a critical safety componentdon't trust unbranded, non certified versions from third party