Developed by the Knight & Hale Pro Staff - each one of these calls are precision-built from custom blended materials. Each one was also designed and tested by champion callers. Included in the Demolition Crew Pro Pack Diaphragm Set: KH 1652 Sweeper - 3 reed for high-volume, raspy, double note yelping. Designed by Steve Stoltz; KH 1654 Terminator - 3 1/2 reed mid-raspy, great for cutting. Designed by Kerry Terrell; KH 1655 Warlock - 3 reed that is perfect for soft seductive yelping. Designed by Keith Wahlig.