Always be ready to measure, calculate and fix anything with The Pocket Engineer. 

Packed with features in laser-cut stainless steel the size of your credit card:

• 26 unit conversions, 7 equations, and 10 physical constants to save you time looking up references in mechanical, civil, electrical, industrial, nuclear, and materials engineering.
  
• Doubles as a wallet ruler and protractor.
• Photogrammetric ruler to calibrate length and tilt in images when used as a scale in field or lab work.
• Pipe inner diameter measurement from 0.25"-1.25" and machinist scale with 10-mil resolution.
• Here's how to use me!