unit is the polished rod which is visible from the exterior of the unit the polished rod moves up and down in a vertical plane when the unit is in operation the polished rod moves through a stuffing box which contain seals that lubricate the polished rod and yet seal the unit to prevent oil leaks these seals are often constructed of graphite or other soft malleable material in order to closely conform to the motions of the polished rod the difficulty with graphite seals or seals of other soft material is that they are not durable seals must be replaced frequently at high replacement cost due to manpower needs replacement materials and down time of the pumping unit yet prior to the present invention it was difficult to engineer hard materials to produce seals of long life and duration a primary object of this invention is the provision of an improved stuffing box for a unit or the like having a seal assembly mounted within a main body thereof there is a seal pack included within the seal assembly which is supported within a seal holder therefor the seal assembly includes a series of pairwise mounted metal hollow conical seals so configured to fit tightly around the polished rod another object of this invention is the provision of slots in the.