FRP Lock (Factory Reset Protection) is the Android equivalent of Apple's iCloud Activation Lock. After a factory reset, the device requires the credentials of the Google account that was last signed in. Introduced in Android 5.1 (Lollipop), FRP is now standard across all Android devices.
For wholesale buyers, FRP-locked Android devices are functionally bricked from a resale perspective. Unlike some iCloud Lock scenarios where partial workarounds exist on older hardware, FRP is robust on modern Android and there is no legitimate bypass: the device requires the original Google account credentials or a documented account-removal flow through the original purchaser.
Wholesale verification: on Android, ensure a sample of stock has been properly factory-reset and walks through the setup wizard without prompting for any Google account beyond the new owner's. Samsung devices additionally have Samsung Knox, which can lock devices independently of FRP; check for Knox warranty void status (Settings > About phone > Software information) on Samsung lots.