Abstract: There is disclosed a press-on cap having a flat top with a cylindrical skirt with an annular tear band defined by a pair of annular score lines, and with at least two annular inner beads which seat in annular grooves in the neck of a bottle. The cap skirt extends below the lower score line of the annular tear band to form a tamper-proof ring which is bonded by laser radiation at least one, preferably two, spots to the neck of the plastic bottle. The spot bonds preferably have a diameter no greater than about 0.15 inch. The invention also comprises a bottle filler line which includes a capping station in which caps are applied and pressed downwardly over the narrow necks of the bottles which have been filled with a liquid such as milk or non-carbonated beverage, and a cap bonding station in which the capped and filled bottles are passed between laser beam effectors which are pulsed momentarily to spot bond the tamper-proof rings of the caps to the necks of the bottles.