A hollow container is formed with a thin-walled, plastic body; and a discrete plastic handle is attached by ultrasonic energy to the plastic body. The handle has a pair of spaced bosses at each end of the handle with a central opening therein to receive an ultrasonic horn. A plurality of integral, energy-directing protrusions are spaced from one another on the bosses to be melted and mixed with the plastic of the container. The energy directors melt first and mix with the plastic of thin-walled bottle to provide a secure attachment. The preferred container and preferred handle are each made of PET plastic.