Accessory for contact plates electric shock devices (marten protection with high voltage plates). The rodents that have penetrated get an electrical shock upon coming in contact with the high-voltage contact plates only when they are simultaneously touching the bulk of the vehicle with their paws. But now there are cars, which are extensively designed with plastic covers. In such cases the touching of the rodent with the high-voltage contact plates will have no effect. It is necessary here that the mass mat is placed near the contact plates, so that the rodent touches it simultaneously with the contact plates. A cable is attached to the mat, which must be connected to the nearest bulk point of the vehicle. If needed, several mats can also be mounted.