Power Supply IRM-03-12 is a part that is currently not Sold by Digi-Key.
Recom Power part number RAC03-12SE/277 (Digi-Key 945-2247-ND) has been offered as a cross.
Output 12VDC 250mA
Same Pinout and Pin Spacing
**Slight Change in Overall LxWxH measurement. Replacement is 1.50" L x 0.96" W x 0.69" H (38.1mm x 24.3mm x 17.4mm)
For more information or to verify this will work for your application see the manufacturer datasheet on the product detail page.