Howler is a Zamperla "Family Gravity Coaster 80STD" model. (The number refers to its 80 meter length.)
There are about two dozen examples of this model. Other "80STD" rides include: Woodstock Express at Dorney Park, Great Chase at Six Flags America, Road Runner Express at Six Flags Kentucky Kingdom, and the Road Runner Railway at Six Flags Great Adventure.
©2010 Joel A. Rogers.