R129: R129 regulations categorize car seats based on the child's height, with an upper weight limit for ISOFIX seats. Unlike R44, there are no predefined groups, allowing manufacturers to approve seats for specific height ranges. This flexibility means seats can cover a wide range of heights, effectively functioning as Combination or All Stages seats.
I-Size: i-Size is a seat category under R129 regulations, indicating compatibility with i-Size positions in certified cars. The majority of R129 car seats fall under the i-Size designation.
R44: These are the older regulations where car seats are classified based on the child's weight. There are five pre-defined weight groups: Groups 0 & 0+ (Newborn to 13kgs), Group 1 (9kgs to 18kgs), Group 2 (15kgs to 25kgs), and Group 3 (up to 36kgs). Some seats are approved for multiple groups, making them Combination or All Stages seats, such as Groups 0+1 (Newborn to 18kgs), Groups 2,3 (15kgs to 36kgs), or Groups 0+1,2,3 (Newborn to 36kgs).