UPPAbaby Infant Snug Seat / Compatible with Vista and Cruz Strollers / 2 in 1 Newborn to Toddler Comfort Insert Designed with infants in mind, the SnugSeat provides extra comfort and stability for your baby's neck and back when strolling. Suitable from 0-3 months requires head and wedge and head support , at 4+ months (or when child can sit up unassisted) wedge and head support removed and used as liner. Updated design features improved head and wedge support while fully covering the toddler seat back. Must be used with Toddler Seat in the most reclined position with insert. Compatible with VISTA,VISTA V2, CRUZ, and CRUZ V2 strollers