This guide will help you quickly identify if you have a 1st or 2nd generation Google Nest Protect, and if it’s battery powered or wired. All generations and types of Nest Protect are compatible and can interconnect with each other.
There are several ways to tell which type of Nest Protect you have. The table below summarizes what to look for if you're trying to figure out if you have a 1st or 2nd gen Nest Protect. If you need to determine if you have a battery powered or wired model, click the link below to skip to that section.
How to tell if you have a battery-powered or wired Nest Protect
| 1st gen | 2nd gen | |
| Look at the side | Straight edges | Rounded edges |
| Look at the design differences without taking your Nest Protect off the ceiling or wall. The most obvious physical difference is the rounded profile of the 2nd gen Nest Protect compared to the square profile of the 1st gen. |
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| Look at the backplate | Square | Round |
| If you take your Nest Protect off the ceiling or wall, you can immediately tell by the backplate design: square for 1st gen, round for 2nd gen. |
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| Look at the Back | No battery door | Battery door |
| 2nd gen Nest Protects also have a battery compartment door, while 1st gens do not. |
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| Serial number (on the back label) |
Serial #: 05A or 05C | Serial #: 06A or 06C |
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| Look in the Nest app | Model: Topaz 1.x | Model: Topaz 2.x |
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How to tell if you have a battery-powered or wired Nest Protect
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You don't need to take your Nest Protect off the ceiling or wall Note: The green light will turn off if there's a wiring problem, if |
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Look at the back If you haven't installed a Nest Protect yet, you can easily tell |
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