Found 3 alternatives for CT03E-04S400-1 by Challenge Electronics. Alarms Buzzers And Sirens — Tape & Reel (TR),Cut Tape (CT).
BUZZER ELECTRO 3V 3.2X3.2MM SMD
AUD. PIEZO XDCR 1-25V
BUZZER MAGNETIC 3V 5.5X5.5MM SMD