Spool holder for Mendel prusa i2 printer

Little add-on for i2 prinetr.
I have spools with 2 sizes (32mm and 75mm) of inner diameter hole.
This holder consists of pair frame holders. and two spool holders.
Rotation is provided by 2 bearings 608ZZ.
This ad-on can be mounted without remove any parts of printer.
additional needs: 2 bearings 608ZZ, 10 M8 nuts, 2 M8 nuts (higher) - to append to printer's frame, 4 M8 washers, 2 M8 washers (big) - to spool holder, threaded rods:2 pieces (cca 150mm length) , 1piece cca 300mm length - may vary according to printer's frame width)

galery description
1 - before using spool holder
2 - mounted frame vertices
3 - spool holder printing in progress
4 - spool with 32mm hole
5 - spool with 75mm hole
6 - fully assembled