When choosing a hand-opened round corner portable kid waterproof umbrella, there are several factors you should consider:

1. Size: Choose an umbrella that is the right size for your child. Look for umbrellas that are specifically designed for children and come in a smaller size.

2. Material: The umbrella should be made of high-quality waterproof material to keep your child dry during rainy days.

3. Frame: Look for an umbrella with a strong and durable frame, such as one made of metal or fiberglass.

4. Design: Consider the design of the umbrella. Look for an umbrella with a fun and colorful design that will appeal to your child.

5. Ease of use: Choose an umbrella that is easy for your child to open and close on their own. Look for hand-opened umbrellas that are designed for children.

6. Safety features: Look for umbrellas with rounded corners to prevent any accidental pokes or scratches to your child.

7. Portability: Look for a lightweight and portable umbrella that your child can easily carry around.

8. Brand reputation: Choose a reputable brand that produces high-quality children's umbrellas and has a good track record in the industry.

Overall, when choosing a hand-opened round corner portable kid waterproof umbrella, it is important to consider the size, material, frame, design, ease of use, safety features, portability, and brand reputation. By taking these factors into account, you can select an umbrella that is suitable for your child's needs and provides reliable performance.