There is two of them. The PM-3 and the PM-4. The difference between the two is that the PM-4 is WIRELESS and the PM-3 is not. They both take the same sound cards too. I have the PM-3, it comes with a 60ft cord to the speaker. The sounds are good on it, I dont think the howls are loud enough but distress ones are awesome. I'm really starting to get sick of stringing out that cord all the time. I've already broke the cord in one spot and had to spilce it back together. The call still works fine. I'm going to buy a Foxpro though. Wireless is the way to go.
Never tried the PM-4