Urea formaldehyde. These resins, used with paper-pulp or wood- pulp fillings, give odourless, transparent mouldings resistant to surface tracking by electrical arc discharges. The mouldings are stronger than Bakelite (tensile strength about 75 N/mm2, compressive strength about 225 N/mm2) and so may be of rather thinner section. They may there-fore be used to make such things as ‘plastic’ cups. The mouldings are still rather brittle, however.