Nania Befix SP Car Seat: The Nania Befix SP car seat is suitable from 15kgs and proves excellent value for money. Features Suitable for Groups 2 & 3. From 15 - 36 kgs (around 3 - 11 years.) Lightweight, easy to carry and fits in most cars. Height adjustable head support grows with the child Padded seat and armrests. Versatile - as your child grows, the back removes to leave a group 3 booster seat.