I have only been turkey hunting for 2 years and only 1 spring so far so take this as you want but from what I have read...it really depends on your area. I own quite a few calls for trying to get a shock gobble. Owl, coyote howler, crow, pileated woodpecker/peacock. So far only one has worked (pileated woodpecker) but again I have only tried one spring hunt so not much experience but I did hunt quite a few days in different areas. Typically gobblers will shock gobble basically when scared. The only other time I heard a shock gobble was walking through the woods right before sun up I tripped and fell snapping a big branch. The crack was quite loud and shocked a gobbler about 150 yards away. Personally I would buy calls in this order from what I have read (owl, crow, then coyote or pileated woodpecker...etc) Most have luck with either owl or crow. If you have tons of owls or crows in your area they may not work since the gobblers are used to those sounds. You cant have enough calls and might as well try them all to see what works best in your area. Good luck!