Popular high-end car seat manufacturer Diono issued a recall for half a million convertible car seats and booster seats from the Radian R100, Radian R120, Radian RXT, Olympia, Pacifica and Rainier lines this week.

Here’s what you need to know if you have one of the seats mentioned in the Diono recall:

According to the U.S. National Highway Traffic Safety Administration, when the seats are secured in the cars with the lap belts, but not top tethers, they may not adequately protect kids who weigh more than 65 lbs. if a crash occurs.

In a statement posted on its Facebook page, Diono notes that if the convertible child safety seat are being used with a lap and shoulder safety belt, with Diono’s Super LATCH system or with a top tether, they aren’t affected by the recall and are still compliant with federal regulations.

“It is highly unlikely that you will be affected by this voluntary recall. To check if you are please answer the following questions,” Diono’s Facebook post states.

The recall is limited to seats manufactured after November 25, 2013, and only affects consumers who are using the seats in forward-facing positions. If you’ve got one installed like that in your car, call 1-855-463-4666 to speak with the Diono safety team.

According to Consumer Affairs, Diono will provide impacted customers with a free remedy kit, an updated instruction manual, an energy absorbing pad and as a new chest clip, all free of charge. The recall is expected to begin November 22, 2017.

Of note: The recall doesn’t apply to Canadians, as regulations in Canada state forward-facing child car seats have to be secured with with the Universal Anchorage System (UAS) or a vehicle belt and the tether.