Let's say, you have a meeting from 2PM-3PM. You set a status "I'm at meeting. Please call me after 1 hour" & set the time from 2PM-3PM. Now if anyone calls you within 2-3PM, he'll get the SMS you set earlier.
1. Can activate auto SMS send for specified time range.
2. Can save custom messages for future use.
3. Starts automatically after phone starts. So you don't need to start it manually.