|The Fresnel lenses in this column are suitable
for wall mounted detectors. They have the same physical dimensions and can be
interchangeable in the same product to get alternative areas of coverage. They are
designed for use with dual rectangular element pyro sensors such as the SPS125B.
||The Fresnel lenses in this column are suitable
for ceiling mounted detectors. There are two available patterns which are interchangeable.
They will function best with single circular element pyro sensors such as the SPS133B