1, you can't send clocks. The bell and the tail are homophonic, which is unlucky. The table is homophonic with the bitch.
2, can not send tools. It's easy to hurt people, and there's an idiom called make a clean break. When you get married, you will feel sad because you gave someone to someone else.
3. You can't send umbrellas. Umbrella is homophonic with dispersion, and dispersion means dispersion. There is a saying that umbrellas are only used in rainy days, and giving umbrellas is to hope that people will spend rainy days often. It's rainy and cloudy, so umbrellas are also regarded as unlucky gifts.