Digital ParkingSensors PSR4000 Digital Ultrasonic Parking Sensors $195.00 Add to cart PSK4 Digital Parking Sensor Add on Kit $117.00 Add to cart GPS4000 Speed Control for PSR4000 Parking Sensor $81.00 Add to cart BUZ04 12V (Louder) Buzzer for PSR4000 Parking Sensor $22.00 Add to cart