There is provided a sandscreen joint (110) capable of providing zonal isolation. The ends of the portion of the (110) are capable of extension on activation of the sandscreen (110), including transition areas (135), which are coated with an elastomer sleeve (134). On activation of the sandscreen (110), the sleeve (134) is pushed out into contact with the bore wall and serves to isolate the zone on one side of the activated sleeve (134) from the zone on the other side of the sleeve (134). Thus, the provision of the sleeve (134) on the activated sandscreen (110) may prevent fluid from flowing axially along the bore between the bore wall and sandscreen. This may serve to protect the weave at the transition area (135), preventing axial flow through the transition areas (135).