Apple launched an iPhone 6s battery replacement program a couple weeks ago and now it has released a tool that’ll help consumers find out if they’re eligible. The program’s page now includes a serial number checker. All you have to do is enter your unit’s number to see if you can receive a free battery replacement.

The program is meant to address a battery problem that has caused units to randomly shut down. It’s an issue that’s present with a small portion of units manufactured between September and October 2015.

Apple will only replace your battery if your unit is in an otherwise good condition.