Most well planned modern attacks are likely to occur at night, under the cover of darkness making night vision critical for security. Thermal or digital imaging along with Gen I, II or III night vision are both necessary tools to have. However, each has their strengths and weaknesses. Click on the word night vision to learn more about the light intensification method of seeing in partial darkness and click HERE to read an excellent article on Thermal Vision which uses heat to see in total darkness but that also has its limits.
Here are some links to good video's and pictures:
http://flir.com/thermoSightR-Series/ Specifications tab - good table comparing models.
http://flir.com/thermoSightR-Series/rangeTest.html Good pictures at different ranges.
For additional information from the Prepper Handbook Block, see:
Blog Table of Contents
Night Vision vs Thermal
Prepper Handbook Table of Contents