controls – Design of an open/closed interval selector

I have a idea to make an “open/close interval selector” to select the value range such as “[0,24]”or “[-1,1]” in mathematics.
[0,24] means “Greater than or equal to 0, less than 24”
[-1,1] means “Greater than or equal to -1, less than or equal to 1”

This control will be use in my project for setting some options value range.
This is the irst edition of my control:

mockup

download bmml source – Wireframes created with Balsamiq Mockups

Yes, looks terrible. Any better idea?