They're not breed specific as such, but many people use an ACME 210.5 for spaniels, and a 211 for labs. No idea why.
There is also a 212 which is often used for field trials.
Sheepdog whistles are different again and I know nothing about them.
All my labs are whistle trained and know three commands. Come in, stop & look at me, and hunt. I use a 211 and a 212.
To teach the whistle start with a verbal command and add the whistle tone you have chosen. So for a 'come in' whistle, choose a tone, eg three peeps and every time you call your dog too you, give a verbal command and whistle signals. I doesn't take long before you can drop the verbal. Calling in for supper is a good way to start it.
The stop whistle is designed to make your dog stop exactly where it is and look at you for instruction. Mine take hand signals at this point. It's taught by choosing a different tone - usually one peep - and blowing it at the exact moment a dog sits down - and can also be accompanied by a verbal command at the beginning. Begin next to you and progress to while walking at heel and then start to work it further and further away from you.
It is a brilliant way of controlling a dog at a distance. Mine will respond from a very long way indeed.