The holders for the tubes in rotators such as this one ( http://www.stuart-equipment.com/product.asp?dsl=137 ) break quite often and once all the limited replacement pieces are gone we were stuck with buying a new machine. Now we can just 3D pint them and replace them. //////////////////////////////////////////////////////////////////////////// Check out our NGO http://trendinafrica.org/ A registered charity run by volunteers that aims at fostering development to Africa through scientific innovation. Help us spread the the word! Donate! Gives ideas for lab designs! /////////////////////////////////////////////////////////////////////////////