Explosimeter gauge.

Fullsize image: https://diqn32j8nouaz.cloudfront.net...r_fullsize.jpg




Previously:

Arc flash electrical box explosion - GIF
Sinking gases cause garage pit explosion - GIF
Electrical box explosion - GIF
Giant transformer explodes in New York City - GIFs and photo
Titanium explosion - GIF and video
Battery explodes while checking machine - GIF