The D-Link DCH-S161 is roughly a 2.7" square white box that is about 1.2" thick. It uses (2) readily available AA batteries which are included to get you started, and houses a built in 90dB alarm siren. The unit comes with a sensor probe with integral cable that is about 6 feet long. It is wall mountable and is operable through the mydlink app, Google Assistant and IFTTT. Surprisingly Alexa is not included on this device.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips