This is a combination set of the bottom pivot and bottom/top guide typically used on a variety of wood bi-fold doors. They are both set a in 3/8 in. diameter plastic housing. The bottom pivot has a tapered grooved tip that fits into the Prime-Line part N 6674 bottom pivot bracket. The 3/8 in. guide is may be used as either the guide pin or as a top pivot depending on the bi-fold door design. To install, lightly tap them into the pre-drilled top mount holes. Used by a variety of bi-fold door manufacturers.