Taking a tiny sip of a piping hot drink is the usual way to figure out its temperature. That, or feeling the cup with your hands, but that can be hard with some materials. The Smart Lid hopes to give you a visual cue, informing you of the drink’s temperature before you use your own body as a thermometer. It turns red when the contents are at 120°F (48°C) or above, which seems like an appropriate middle ground. The lids come in packs of 1,000 of either the lid alone, or the lid with a 8oz or 12oz cup, with prices starting as low as $62. Clearly restaurants will have more use for this, but there is a 40 lid/cup pack for $30 that you may be tempted to use at home.