The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Alex Aliferis:
Drum Factor X delivers a super-expressive, easy-to-use percussion (and more!) player to your portable device. Position-sensing performance pads combined with advanced audio pre-processing allows for users to create subtle or extreme changes in sound, depending upon where inside a pad a touch occurs. For example- tapping the outer area of a pad playing a ride cymbal sound will respond realistically, giving the effect of hitting a real cymbal at different positions along it's surface.Melodic presets are also provided in addition to multiple percussion-based kits.To change kits, simply tap the up and down arrows on the left and right of the kit name. Enjoy!