I have the Omega cold light diffusion head, came with my enlarger along with the condenser head when I bought my D3 in the mid 70's. I don't think it is "good" alternative to an Aristo head. Mine has one fluorescent tube and is slow and difficult to focuses. I only use graded paper's with 5X4 and 6X9 negatives. I have even considered taking my head to a lamp repair shop to see if a smaller tube can added to to inside of the existing tube increase the brightness. Given a choice I would think twice about an old Omega cold light.