What about bends in the Sun Lite system?

For maximum effectiveness, the tubes should be as straight as possible. However, since it is often impractical to site the ceiling diffuser directly below the roof mounted glazing, the rigid tubing system allows an offset by means of two elbows, one at roof level and one at ceiling level.

They are adjustable up to 30° from vertical. There should be no other bends or offsets in tubing as monitoring has shown that these will adversely affect the performance of the system. The flexible tubing offers easier installation, however, the down side of flexible tubing is the reduced reflective performance.