"it rocks !"4.0 starson by itsdigger
Pros: easy to install, very small (1inch x 4inches), added a a bunch of punch to my headphones( by the way ,i'm using it on my laptop) really gave me the extra power to wake up the headphones
Cons: I purchased the AC powered version and the manufacturer should install an on/ off switch, it's always on
Summary: I'm using this amp in conjunction with the DFX audio enhancer for Windows Media Player and it I have to say that as big a musical snob that I am that I'm very impressed with this product and would suggest anyone running headphones on a laptop to purchase this.