This app uses the proximity sensor on your phone,sensor detects your hand waving over screen and perfrom the desire functionality.
You can turn on the loud speakerphone while answering the call if you are not using headset.
When you wave your hand or bring your phone close to your ear, proximity sensor detects the incoming call and answer it.
Speaker on when answer calls:
you can optionally choose to turn speakerphone on while accepting call.
When your hands close to the proximity sensor, it will allow the phone to reject the incoming call.
Send sms when rejecting calls:
when you reject the call, you will send sms to caller, you can specify the text which you want to send back to caller whose call is being rejected.