The AiM Infrared Receiver is a spare or replacement Receiver that is installed in your race car and receives the lap signal from the infrared transmitter.
The AiM Infrared Receiver sometimes referred to as an Optical Lap Reciever is installed in your race car and receives lap signals from the infrared transmitter positioned at the side of the track. It just needs to be pointed to the side of the track where the transmitter is installed to be able to read the signal.
It is also available with a 4 pin metal plug connector.
The car infrared receiver is available with a 300cm lead, it is also available in a 90cm lead for bikes/kart, although there is nothing stopping you from using the lead that best suits your requirements.