Easy alignment tools. A perfect alignment between transmitter and receiver is key to optimise the operation of the active beams. To make the optical alignment easier, the SL-350QDP chassis features vivid yellow colours to be seen from the distance and the "Sniper Viewfinder" , a telescopic lens magnifying twice the distance inside the beam. A sound gauge fitted in the receiver validates the accuracy of the optical alignment. For the fine tuning, the SL-QDP receiver is fitted with five LED to indicate the level of the signal received from the transmitter ranging from poor to excellent. Weather resistant. IP65 rated, the SL-350QDP housing has been designed to resist against both water and dust. The two hoods featured on the front cover are positioned over the upper and lower beam to prevent frost from attaching to the cover and potentially affecting the signal power. The housing is made of UV resistant polycarbonate material to avoid deterioration caused by ultraviolet rays to maintain good transparency for the infrared beams over time. Additionally, the beams are fitted the light disturbance compensation circuit differentiates the beam signal from other external light sources.