Durst M601 Sivoneg Universal Carrier Issues
The carrier I have for my 601 is a blue/grey metal unit with red plastic bits to move the masking blades. There should be two black plastic pieces sticking up from the rear of the lower section. These are the negative guides which slide forward or back for 35mm or 6x6. I have glass in the lower section and a 6x6 mask above. For 35mm you could do the same, or use masks top and bottom for a glassless carrier. The glass I use came from a carrier for a different model enlarger, but it was the right size. Have a look around on eBay, etc and you may be lucky.