For affixing your T1 type mini red dot sight to a standard accessory rail, this mount places your sight about 30mm higher then the rail surface.
Though not used much in Airsoft, the ability to mount your scope higher is still a valid option for those who need the taller clearance. This may be in order to place the scope clear of a blockage in front of it such as a flashlight or laser or may just be a measure to allow use with a big pair of goggles.
It is called the light weight version because it forgoes a more complex attachment in favor of a simple pair of screws to keep things simple and low mass.
Aluminium mount with a dull black surface finish.