An addition to my other remarks.
The HO (R17D) connection ends (not FA8) are fully adjustable in all directions.

I bought these 8'-0 LED HO (FA8) end connection tubes to convert my old fluorescent fixtures. Very easy wiring conversion. Hot to one end, neutral to the other end and remove the ballast. (Ignore the wiring diagram on the carton and go with the wiring diagram on the website.) I went with the 6000 K, clear tubes because my ceiling is 14 FT. high. I'm half done and in an area approx. 18 ft. x 25 FT. with 6 fixtures (12 bulbs), the lighting is excellent ! The ends fit perfectly and didn't seem to sag in the middle. I did zip strip the center of the bulbs to prevent any possible future sag. Shipping was very fast (1 week) from China. Sezer was very good with all communications ! I would buy these again.