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.
Unlike the light weight version (GP-MOT005) this model gains a little weight (only 10g though) and a bit more bulk to accommodate a QD throw-lever style mounting system.