Two ladies came to our office and presented a wearable safety alarm that they design and distribute. They are small and easy to carry and can attach to a purse or backpack or belt, etc. They are simple to use. If you feel threatened or are threatened, you simply squeeze the alarm and it emits a loud noise designed to startle the person threatening you and to alert others in the area.
The alarm is only $22 (bling out it is $30). Check out their website at https://www.2shelleys.com/