In the spirit of the spool holders based on 4 bearings.It measure 112 x 55 x 8 mmThis one is made to fit 240mm diam. spool, 55mm from inside to inside (minimum, you can use longer bolt for larger spools).That's the stratasys old Dimension spool found in their cartridges, the case is great but you can't see how many filament you have, thus I wanted to take it out.[15/03/2012] added one for 50mm (smaller) spoolAdd 4624 bearing (bearings that fit 4mm diam. bolt) 4M4x16 bolt (or longer) 4 or 8 mudgard washer 8 or more M4 washer (as many as needed for the spacing)