Big Cheese Anti Mouse Mini-Sonic Mouse Repellent. The Big Cheese Anti Mouse Mini Sonic Repellent is the next generation of ultrasonic rodent deterrent. The discreet unit is smaller so when plugged in it doesn’t obstruct the neighbouring socket. Despite the smaller size, it still remains fully effective in humanely deterring rodents. The repellent is easy to set up and use and doesn’t require any batteries. Simply plug the unit into an electrical socket and switch on. Use one repellent device per room. Keep the device switched on whilst controlling an infestation, or use it as a preventative against the return of rodents. The unit releases ultrasonic sound waves which only rodents can hear. The sounds cannot be heard by humans or other non-rodent pets, and create an acoustically hostile environment, causing the rodents to move away and find an alternative habitat. It shouldn’t be used around rodent pets such as gerbils, hamsters and guinea pigs as the sound will be within their hearing range.