Knight & Hale turned up the volume of the original Pack Rack for 2010 with the new Pack Rack Magnum ($24.99). It's a little larger than the original, but that's understandable because its purpose is to replicate the sounds of two 160" bucks fighting.
To use it, simply put the faces of the two sound plates together and turn them in opposite directions. The more pressure you apply, the louder the sound. Tone can also be adjusted by changing the firmness of your grip on the handles. Technically a big whitetail call, it can also be used to attract elk, muleys, and moose.
Contact: Knight & Hale Game Calls, (256) 353-0634, www.knightandhale.com.