Plot hole: They need at least 12 magnets to make it work, Paige collected 11. (00:21:00 - 00:22:00)
Other mistake: When Happy goes to see if the backhoe will work to finish freezing the water she says the hoses are damaged. The hoses she indicates as damaged are the ac lines and hydraulic lines that hydraulic oil flows through - she does not even look at the water hoses. (00:18:40)
Answer: They are a real device. You can find more information online. Just google "stun-cuff."
raywest