Here's what Westside Discs has to say about the Harp:    

The Harp is Westside's most reliable approach disc. Designed to withstand and type of conditions. It will hold in the wind. For professional players this could be there only approach disc they will need to carry as it can hold anyone's arm speed and still hyzer. For slower arms it will be your most over stable approach disc. 

Speed: 4 Glide: 3 Turn: 0 Fade: 3