I use this part with Eheim classicLED daylight 13W 740mm, Part No. 4262011.
The brown plastic part from classicLED fits on a 3mm frame on top of the Eheim Aquarium. I use an standard Aquarium with 6mm glass. The printed part rises the LED about 80mm above the top of the aquarium and fixes its Position, you need at least 1mm space inside to fit the riser on the glass.
The riser is printed in two parts. I used PLA. On one set i glued it together with CA (Superglue), the other is put together with M3x16mm Screw and m3-nut. There are three holes for m3 screws, you need only two.