Here's a page with some reviews of what appears to be the same product: DX New Forum – Discuss Cheap Electronics and Find Smart Tech Here. From what the reviewers say, the output is unamplified, and the single integrated circuit on the board is a comparator rather than an amplifier. Conventional wisdom says you need amplification on the order of 100X with an electret, on a 5V system. In order to use it meaningfully, you will probably have to add an op amp. You can see how sparkfun did it, here - https://www.sparkfun.com/datasheets/BreakoutBoards/Amplified-Mic-v10.pdf.