At less than $20 a piece .. Aquaz should be the best value for money T5 parabolic reflector at the moment.
It comes packaged with 2 plastic snap on C-clips that snaps on tightly to the reflector. The C-clip can "swing" slightly from side to side to accomodate the movement of the tube. The overall design of the reflector is good and its light yet rigid enough.
However, I personally would like to have predrilled holes for mounting of the reflector. The inverted "V" makes it difficult to drill holes.
