GPS trackers are generally safe for pets of various sizes, as long as the device is appropriately fitted and not too heavy or bulky for the animal. Most pet GPS trackers are designed to be lightweight and comfortable, ensuring they don't interfere with the pet's normal activities or cause any irritation. However, it's essential to choose a tracker that is suitable for your pet's size and weight. Smaller pets, such as toy dog breeds or cats, may require more compact and lightweight devices to prevent discomfort or restricted movement. It's always a good idea to consult with a veterinarian to determine the best GPS tracker option for your pet's specific needs and to ensure a proper fit.