Diono Radian 3QX SafePlus expiration
The Diono Radian 3QX SafePlus expires 10 years after its date of purchase.
Check your Radian 3QX SafePlus
What to know
The 3QX is the slimmest of the Radian line and shares the 10-years-from-purchase policy. Diono's booster-mode article gives 120 lb and 57 in as the upper limits.
The date of manufacture is on the seat itself. The date of manufacture is on the serial label on the seat, on the back or underside of the shell depending on model, along with the model name and number you need for Diono's support lookup and registration.
Safety note: SeatCheck summarizes manufacturer and NHTSA guidance, but the label on your own seat and its manual are the final word. When in doubt, contact the manufacturer with your model and serial number.
More about Diono seats
Full policy, label locations and crash-replacement rules on the Diono brand page.