Mobile Rack:  SI-121A Hot Swappable IDE Backplane  
Features:
Fits three 1 HDDs into two 5.25" bay
Front door with ID Display
 
Specifications :
Form Factor 3 drives in 2x5.25 bays
Drive Interface IDE 40 pin
Host Interface IDE 40 pin
Color Beige and Black
Fans 1
Indicators Power, Audible Alarm for fan and hard drive failure
Dimensions 3.34"(H) x 5.25"(W) x 9.76"(D)
Weight 7 lbs.