A hemostasis valve assembly comprising: a housing; a cap coupled to the housing; and an elastomeric member at least partially disposed within the housing, the elastomeric member forming a variable-width channel that extends at least partway through the elastomeric member; wherein the elastomeric member comprises: a first protrusion defining a first diameter, the first protrusion is inward-extending and forms a first cylindrical sealing surface; a first relief space defining a second diameter that is larger than the first diameter; a second protrusion defining a third diameter, the second protrusion is inward-extending and forms a second cylindrical sealing surface, wherein the third diameter differs in size from the first diameter and is smaller than the second diameter; and a second relief space defining a fourth diameter that is larger than the third diameter; wherein the first protrusion is proximal of the first relief space, the first relief space is proximal of the second protrusion, and the second protrusion is proximal of the second relief space; characterized in that there is provided a foam member configured to secure the elastomeric member at least partially within the housing and provide additional structural support adjacent the proximal end of the elastomeric member, wherein the foam member holds lubricious fluid that eases insertion and removal of various elongate members, wherein the first cylindrical sealing surface has a first height of between 0.25 mm and 0.45 mm, and the second cylindrical sealing surface has a second height of between 0.25 mm and 0.45 mm, and wherein a circular recess extends into a proximal surface of the elastomeric member, the circular recess engaged with and coupled to a protrusion of the cap. a housing; a cap coupled to the housing; and an elastomeric member at least partially disposed within the housing, the elastomeric member forming a variable-width channel that extends at least partway through the elastomeric member; wherein the elastomeric member comprises: a first protrusion defining a first diameter, the first protrusion is inward-extending and forms a first cylindrical sealing surface; a first relief space defining a second diameter that is larger than the first diameter; a second protrusion defining a third diameter, the second protrusion is inward-extending and forms a second cylindrical sealing surface, wherein the third diameter differs in size from the first diameter and is smaller than the second diameter; and a second relief space defining a fourth diameter that is larger than the third diameter; a first protrusion defining a first diameter, the first protrusion is inward-extending and forms a first cylindrical sealing surface; a first relief space defining a second diameter that is larger than the first diameter; a second protrusion defining a third diameter, the second protrusion is inward-extending and forms a second cylindrical sealing surface, wherein the third diameter differs in size from the first diameter and is smaller than the second diameter; and a second relief space defining a fourth diameter that is larger than the third diameter; wherein the first protrusion is proximal of the first relief space, the first relief space is proximal of the second protrusion, and the second protrusion is proximal of the second relief space; characterized in that there is provided a foam member configured to secure the elastomeric member at least partially within the housing and provide additional structural support adjacent the proximal end of the elastomeric member, wherein the foam member holds lubricious fluid that eases insertion and removal of various elongate members, wherein the first cylindrical sealing surface has a first height of between 0.25 mm and 0.45 mm, and the second cylindrical sealing surface has a second height of between 0.25 mm and 0.45 mm, and wherein a circular recess extends into a proximal surface of the elastomeric member, the circular recess engaged with and coupled to a protrusion of the cap.