Pepper spray, girls can carry one with them at all times, it would be very useful when they encounter a bad guy. "When they can't see, they can't hurt you."
DIY pepper spray:
Dry ingredients: 500g dried red chili, 100g pepper powder, 100g Sichuan pepper
Fresh juice: 500g green chili juiced, 100g ginger juiced, juice of two lemons
1000ml water, heat up and add dry ingredients, boil for 15 minutes, then add fresh juice, keep boiling uncovered until the soup is reduced to half of its original amount, add appropriate amount of salt.
Cool down and filter out solid materials with gauze, filter several times until only liquid remains.
Put into bottles and it's ready to use! This liquid can also be edible, add a few drops when eating noodles, it tastes better than chili oil.
PS. If you don't need the edible function, you can also add green onions and garlic.