Abstract: A fragile article such as an electric lamp having a glass bulb of spherical, paraboloidal or general pear-shaped configuration is protectively packaged by inserting it into snug slip-fitted relationship with an open-ended hexagonal sleeve-like carton of boxboard or other suitable packaging material. Parts of opposing walls of the carton are cut, scored and interconnected to provide a foldable flap assembly that is automatically actuated when the carton is expanded from collapsed condition and is then converted in "snap-like fashion" into a laterally-extending platform that locks the carton in its fully-erected tubular configuration. The platform is provided with a suitable aperture which frictionally grips the basal end portion of the inserted lamp and thus holds the lamp in loaded position within the carton.