Here's a subtle one: the draw. Genuine devices have a smooth, consistent airflow. Fakes often have a whistling sound or feel airy, like there's a gap somewhere. When you inhale, you want a steady pull. If it feels off, trust your instincts. Also, listen to the device when you shake it gently. A rattling sound can indicate loose parts inside—another sign of poor assembly.

These audio cues are easy to miss if you're not paying attention, but they're a quick way to spot a fake without opening anything.