Overview Reviews Product Description Von Duprin 900-4R Power Supply 4 independently controlled relays to power multiple devices Optional Fire Alarm Emergency Interface Relay available Product Videos Custom Field Product Reviews (No reviews yet) Write a Review Write a Review × Von Duprin 900-4R Von Duprin Power Supply Board Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *