The candies converter is an unlockable item in Candy Box. It is accessed by completing the Castle's stairs quest. It allows conversion of candies into lollipops on a one-to-one basis. 

The rate at which the conversion occurs speeds up over time, so long as you leave it running.

from candiesConverter.js:

// We increment the speed
if(this.speed < 10000) this.speed += 1;
else this.speed *= 2;

This means that  it converts candies to lollipops at a rate of 1 candy per 1/10 second (it doesn't say this in the picture, but it does in the source code). It increases by 1 candy each conversion. At the end of the first second, it will have converted 55 candies into lollipops. When it reaches 10000 candies per 1/10 second, the amount converted will double each conversion. This makes it give you lollipops MUCH faster and makes unlocking all the bugs in the computer much easier. It takes 16 minutes and 40 seconds for it to reach this point. 

Source code found at

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