I grabbed myself a new enlarger, a De Vere 54b. It's built like a tank and has a full set of condensers. Thing is, I know nothing about its neg carriers. I have a set (135, 6x6, 6x7, 5x4) of circular holders that fit into a specific drawer and I have another drawer which I presume takes rectangular carriers (of which, I have none). Now, I'd prefer not to use glassless carriers. I want to go glass, but what do I need to know? Will these circular holders take glass? (I presume they won't as there's nowhere for the glass to go.) Do I need to buy special carriers? (If so, what models should I be looking for?) What's the difference between the circular and rectangular carriers? (Apart from the shape...) Is there even such a thing as a glass De Vere carrier?