The normal size hasa 160mm internal (max roll size) and 32mm post diameter (max hole size).

A new jumbo version has a 180mm internal and 38mm post diameter to accommodate larger rolls.

After adding the towel roll with the end free, spinning the roll clockwise should automatically feed the end out of the side slot. Tear a sheet off by pulling from the bottom upward and towards the right edge of the slot.

Feel free to increase the holder's height. I chose 180mm high to fit my bed, and I don't think I would go much shorted, but I think taller wouldn't hurt.

Print with draft settings to speed up the print. I used 0.28mm layer heights and height modifiers to set the base infill to 30% to increase weight, and 15% infill for the rest.

Add three rubber pads or feet to help prevent sliding. I have a spot on my workbench paper towels live, so I just may attach it with some double-sided tape to create a semi-permanent home for a roll.