The product is a set of OEM front rear left right brake pad wear sensors for Mercedes Benz R107 W123 4PK. Manufactured by Beck/Arnley, the sensors come with a 1-year manufacturer warranty. The sensor type is brake pad wear sensor, and the interchange part number is 1405401217. The sensors are designed for left placement on the vehicle and are considered a superseded part number 140 540 12 17. Made by BOWA OEM, this set includes 4 sensors to ensure comprehensive coverage for your vehicle's braking system.