I use ACME retriever whistles on 211 ½, which the manufacturer says the dog hears depending on the wind and terrain up to 1.5 kilometers away.
One of the first whistles to teach a puppy is the come whistle.
HERE
For an average Labrador puppy, food is of great value in the first few months and mealtime is the best part of the day, which is why many people start training the come whistle around feeding time. Have the puppy's food bowl ready and wait for the moment when he is calmly somewhere far enough away from you that he has plenty of room to run to you. Run, not limp, because you want the dog to run to you when you hear the come whistle in the future, not walk.
Get a whistle ready and show the puppy the bowl from a distance while whistling two quick signals (pip-pip). When the puppy reaches you, put the bowl down immediately. Once you've done this dozens and dozens of times, make it a little more difficult and whistle when the puppy is a little further away and can't see the food bowl yet. From there, take the exercise to different rooms, the yard, or anywhere in the environment. Don't forget to reward your puppy for coming quickly.
STOPP (stop, sit and watch).
When the stop whistle is blown, the dog must stop quickly, sit down (or stand) and look at the handler for further instructions. Usually, a slightly longer whistle is used for this, for example 2-3 seconds long (piiiiiip).
For a small puppy, you can start training the stop whistle near the front door, for example, when the puppy will wait and sit. You can also take advantage of the moment when the puppy is waiting for the food bowl to be lifted to the floor and offer to sit and wait. As soon as the puppy sits and looks at you, praise and reward him.
If this goes well, take this exercise outside and give the whistle while walking, while the puppy walks beside you. Also, stop when you hear the whistle and gently reward the puppy as soon as he sits and looks at you. Later, you can start to turn to face the puppy and quietly increase the time you sit and wait, or your distance from the puppy. Do not give the whistle when the puppy's attention is completely elsewhere, give the puppy a good chance to succeed initially.
LOOK FROM HERE (nearby search)
The purpose of the close search whistle is to signal the dog that he is in an area where an object (dummy, bird, small prey) needs to be found. Upon hearing this whistle, the dog should put his nose down and start doing strong nose work in a small radius, where he is currently located.
There are many different types of close-range whistles, and this is where it gets interesting. Some people use a series of short whistles (for example, 5 short whistles - pip-pip-pip-pip-pip). If it feels comfortable, use it. Another common signal is one or two short whistles followed by a long, descending whistle (pip-piuuu, pip-piuuu). Choose a signal that is comfortable for you and different enough from other whistle signals you use.
You can teach the short-range whistle on a sniffing mat, a 1 x 1m patch of grass, or in snow with treats or dry dog food sprinkled on it. Leave the dog sitting in front of the grass or mat, with his back to the treats. Give the short-range whistle and direct the dog (with your hand if necessary) to look behind him for the treats. Praise him with your voice when he stays in the right spot, call him back when he expands his search and switches from nose work to looking with his eyes and running around.
Happy whistling!
