Phenolic Kraft starts as our electrical grade Kraft and is impregnated with phenol resins before we get it.  It is designed for electrical applications giving more strength than Kraft alone with the same wall thickness.  It also is moisture resistant and retains it's shape better than Kraft alone allowing machining like notching or drilling.  It is a high calendared sheet and becomes much stronger after it is cured in our oven and has the same electrical properties as Kraft at 180 volts per mil.  Our tubes are 'spiral wound' and considered XX grade. 

    XXX grade tubes are 'convolute wound' and vacuum impregnated with phenol resins after the tubes are made.  Typically, they will be ground to the final OD and will not have a spiral line around the tube.  We CANNOT make this type.