Manually lock a recording?

[minus4]

Doing some research before purchase. I'm trying to figure how to manually lock a recording on DR900X-2CH Plus. I do see this function on Blackvue's manual, but can't seem to find a button on the photos and video reviews I've seen. Can anyone tell me how it's done?
Thank you.

 

[DashCamMan]

That model has a proximity sensor that can be configured to manually record files.

 

[minus4]

That model has a proximity sensor that can be configured to manually record files.

View attachment 60810

Thanks for the quick reply! I tunnel visioned into a physical button, and didn't notice this part at all!