Smart Ruler Pro is the 1st set of Smart Tools collection (ruler, protractors, level, thread). It integrated 6 simple and useful tools into this app. Here is the list. 1. Ruler - length2. Protractor? (Touch) - angle3. Protractor? (Plumb) - slope4. Protractor? (Camera) - goniometer, clinometer5. Surface level - sprit level6. Thread pitch - screw, bolt, nut. Pro version added Features: - No ads - Multi-Touch mode - Caliper mode - Ruler Extension - Architectural and Engineering Scales - Various Tilt units. Do you want more tools? Get [Smart Tools] package. For more information, watch YouTube and visit the blog. Thank you. No internet support : You can open this app without any connection. After installation, open the app 2-3 times with your device connect to WI-FI or 3G/4G.