The Power Calls Fuel Combo includes the Fuel Crystal and Batwing Dome. The Fuel enables higher frequency cuts and yelps that sometimes triggers a response from hung-up gobblers with its crystal-over-glass surface. The venerable Batwing Dome mouth call is designed to deliver the full turkey vocabulary. Fuel Crystal: Crystal over glass Matched purple heart striker Fuel Cap snap-on protective lid Surface conditioning pad includedBatwing Dome: Mouth call Batwing cut Metal dome Order today!