Same specification line
Ask each plant to repeat capacity, neck finish, glass color, lid set and decoration process on one line. If a plant substitutes 70 ml for 60 ml or changes a lug to a continuous-thread, treat that as a new construction, not a silent equivalent. Burst strength and drop-test methods, when requested, should name the method and apply to the shipper, not the glass wall. A 2 oz spice blank and a 16 oz pantry jar cannot share that line.