I've had e-callers since they first came out, before that cassette tapes on a Sanyo portable. The latest one is a FoxPro Fusion and it is a truly amazing device. It can hold up to 1000 calls and stand call sequences, it comes with 200 calls and there are many free calls to download on their site, or to buy. The customer support is probably the best or one of the best groups that I have dealt with for help on anything I have bought. The call has several features that you can use to combine calls, manipulate the speakers by fading one side out to mimic movement. It also has a feature called foxbang that initiates a new call or sequence after the gun is fired
The call is small and has all the volume you need although it has a jack for a aux speaker.it also has a jack for a decoy that you control with the remote, and it has good range, I used it on crows from 300 yards away without a hiccup.
So for deer, moose, coyote, bobcat, or anything you want to hunt, its one of the best.