Specifications: The parking aid system usually works with the help of ultrasonic sensors and short ultrasonic waves are transmitted to the control unit where they are analyzed. The parking sensor detects obstacles and determines the exact distance and inform the driver of the remaining distance by warning tone or optical display. The improvement of signal strength enables the driver to brake in time when parking. Item Name: Reversing Sensor Material: ABS, Plastic Compatible Models: for BMW 1 E81   (02/2006 — 12/2011) for BMW 1 E87   (02/2003 — 02/2007) for BMW 1 E87 LCI   (01/2006 — 06/2011) for BMW 1 E88   (11/2006 — 10/2013) for BMW 1 E82   (11/2006 — 10/2013) for BMW 3 E90   (02/2004 — 09/2008) for BMW 3 E91 LCI   (07/2007 — 05/2012) for BMW 3 E92   (05/2005 — 02/2010) for BMW 3 E92 LCI   (11/2008 — 06/2013) for BMW Z4 E89   (01/2008 — 08/2016) Features: Accurate, Easy to Install, Durable Size: 4.2cm x 3.8cm x 2.8cm/1.65" x 1.50" x 1.10" (Approx.) Notes: Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Reversing Sensor