This toy is essential to your dog for many reasons:

Mimicking Prey: The sound of a squeaky toy can mimic the noises of small prey, which can activate your puppy's hunting instincts and provide mental stimulation.
Entertainment: The novelty of the sound can provide entertainment for your puppy, keeping them engaged and preventing boredom, especially when they're left alone.
Exercise: Chasing and playing with the squeaky toy can provide physical exercise for your puppy, helping to burn off excess energy and promote healthy activity levels.
Training Tool: You can use the squeaky toy as a training tool to reinforce positive behaviors such as fetching, as the sound can act as a reward for desired actions.
Bonding: Playing with your puppy using a squeaky toy can strengthen the bond between you and your pet, as it creates positive interactions and shared experiences.

Notice: 

Due to personal measurement technique, there may be a 1-3 cm error of physical difference.Thank you!