Our spool rack is essential for sectional warping.  Ours will hold up to forty 4″ spools and has a center post that pivots for easy loading and unloading.  The center post locks into place during use.  Even though the spool rack is generally used for sectional warping.  It can be indispensable for other studio tasks as well: holding standard yarn tubes and bobbins or as a place to clamp a swift or ball winder.  Our spools are made of cardboard and measure 4″ wide with 3″ flanges.