calls from such companys as vermanater,carlton,cronk,primos,sceery,quakerboy,a re just to name a few.there all good calls that do the job.if your in an area where its cold then open reed calls should be looked at. but theres alot of good closed reed calls out there but they will freeze up on you.diaphram calls work good.as far as who makes a diaphram made for predator huntin,i don't know i just use my turkey calls.i think primos,sceery and quakerboy make some.go thru your turkey diaphrams and see what ones sound like a distress sound,some work others don't.i like the heavy double latex ones,they seem to sound the best.some of the cuttin type diaphrams don't work as well.if when you go to gander mountain you see one labled"howler diaphram"get it.they also work good for distress sounds.