The watch band uses food-grade silica gel so users don’t suffer allergy when put it on. It’s recommended that user wear the band and leave one-finger space between the band and wrist. Because human muscle will become bigger when temperature changes or after workouts and user might feel tight if there is no such space before.
Yes, you can, and very easy.
Most smartwatches are free to change the strap, so you can keep your smartwatch clean and fresh for a long time. According to different occasions and clothes, you can choose different colors and styles of the strap, and very simple.