SpectrAlert Advance, the broadest and most versatile line of notification devices available, includes a wide range of devices to meet emergency communications application requirements. ALERT-printed on white housings amber lens strobes and speaker strobes provide visual signaling for emergency communications in compliance with ANSI/UL 1638 — Standard for General Signaling Visible Appliances. Other Plain or ALERT-printed models provide clear lenses for use with color lens strobe attachments (amber, blue, green, and red) that easily attach to strobe and speaker strobe devices without a candela derating.