Just what it says.... Both power up when plugged in, and have holders for use in Omega enlargers. The holders look like the outer casing of a condenser for a D series enlarger, and have an opaque piece of plastic on the bottom. Aristo D2 $75 Zone VI $90 Feel free to give reasonable offers, also. More enlarger parts available, such as negative holders, lens boards, turrets, etc. Feel free to ask. Paypal or money order preferred. Shipping is extra. Thanks!