Why do I have .SEC files? (YI LITE Action Camera) .SEC files are much lower in bit-rate which allows you to quickly preview videos on the app. Related articles How do I download videos and photos from the app?(YI LITE Action Camera) What is a .thm file? What is the Electronic Image Stabilization(EIS) function? How to use it？ How many GB of storage does the YI Lite Action Camera come with?