This is the FredTech Brake Master Cylinder Brace for the 2006-2016 Lexus IS250 IS350 and ISF.
 
Click here to a full installation video: https://www.youtube.com/watch?v=dQclwNyWZ7g&t=2s
 
During hard braking, the firewall where the brake master cylinder is mounted will flex, hindering pedal feel and reducing the amount of force being transfered to the brake pads. Bracing the brake master cylinder will elimianted firewal flex, improving pedal feel and allowing for more force to be applied to the brakes. 
Slight modifcation/rotation to the fuse box is required to bolt on this brace.