Caliper in your pocket: Millimeter and Millimeter Pro - screen ruler for Android and iOS.

With Millimeter and Millimeter Pro applications for Android and iOS
you can make quick estimation of length, width, radius and area of small objects and parts if you don't have a ruler at hand. Millimeter Pro version can be also used as Thread Pitch Gauge. More info...

Option menu on Samsung Devices.

"To access the hardware menu button in Galaxy S5, you can simply tap and hold Recent apps button."

If you have troubles of finding option menu button on some Samsung devices please check this article:

http://galaxys5guide.com/samsung-galaxy-s5-how-to-guides/how-to-access-the-hardware-menu-button/