What are weight restrictions and harness slot height requirements?

The Radian 3RXT Safe+ has a rear-facing range of 4 to 50 lbs, forward-facing range is from 22-65 lbs when using the seatbelt system or up to 40 lbs with LATCH. There are five sets of harness slots on the back with proper height according to child's weight and age: always use top three for forward-facing positions; remove crotch strap in booster mode if applicable (must be at least 40 lb). Use safe stop device between harness straps and frame when used from 22-40 lbs exclusively. Move chest clip up or down as needed but it should always remain near the child's armpit level (Pages 8, 9, 37–41 ).