Needle-spring locking device for pump-injectors of diesels, in which in order to significantly increase the lift and closing pressures of the nozzle needle, the locking spring is disposed in the central cavity of the body around the outer surface of the plunger’s bushing and is connected with the needle via a transversal cross-arm disposed in the plunger bushing. The preparation contains a nonionic, amphoteric or cationic surfactant in an amount effective to eliminate or substantially ameliorate burning pain caused by capsaicin. For example, a peelable seal can also be made from a mixture of an ethylene polymer with a melt index in the range from about 0. The side walls include airflow openings on opposite sides of the cage member.