Some manufacturers may not have a fixture represented as yet.  As time permits more fixtures will be added.
All manufactures listed produce at least one "Full Cutoff" fixture or fixtures that help preserve the dark sky.

Much effort has been expended to organize the fixtures into logical categories. 
Due to the nature of the industry this has been difficult because of an inconsistency in terminology.

IDA has been asked many times to certify or endorse specific fixtures.  IDA does NOT endorse products or manufacturers. One of the reasons is because all fixtures can be installed improperly and used in improper ways.

Not all fixtures presented are "Full Cutoff" because some categories may be limited in product availability.
Some applications may limit the use of "Full Cutoff" fixtures. 
In all cases where "Cutoff" fixtures are shown they represent the highest performance we know of for such fixtures.
In most cases the "Cutoff" fixtures shown on these pages exceed typical "Cutoff" fixtures but fall short of "Full Cutoff".
The term  "Full Cutoff", when used here is based on the visual appearance.  See IS-143
When the manufacture has a "full cutoff" statement in the literature the term "IES Full Cutoff" is used. 
The same applies to "Cutoff" and "IES Cutoff".
It is our intent to develop some type of cutoff ranking validation.  That is the task of the Working Group.

Some pages may be ranked by performance; most are not.  Position on the page has no relevance.
When a page contains "Full Cutoff" and "Cutoff" fixtures, "Full Cutoff" will usually appear first then "Cutoff".
A "TLC" thick gray line will separate "Full Cutoff" and "Cutoff" with some notes about the fixtures or category.

No attempt has been made to favor one manufacturer's product over another in ranking fixtures.
No attempt has been made to favor one manufacture over another although we note IDA membership.
Again listing on this web site is not an endorsement of a specific fixture or manufacture.