WindTrig is an app designed to dynamically calculate crosswind, headwind and tailwind components easily without needing to press a "calculate" button every time. It is especially helpful in expeditiously calculating wind components to figure out if you are within your airplanes crosswind and headwind limitations.
Most airlines have headwind and crosswind limitations for CAT II and III approaches as well as contaminated runway crosswind limitations. This is an easy and accurate way to find out without needing to refer to a paper wind component chart.
This app also serves very nicely as a teaching tool for CFIs wanting to teach their students how to calculate crosswind and headwind components.
Angle mode allows for fine adjustments of wind angle down to a resolution of 1 degree.