Honeywell 621-4550 Description Description Honeywell 24V DC Source Input Module Related products HONEYWELL AX51-061-001 HONEYWELL 620-1690 HONEYWELL 620-0053 HONEYWELL STD924-A1A-00000-MB.3H+XXXX HONEYWELL 621-9990 HONEYWELL 620-0090