An assembly comprising: a procedural sheath, said procedural sheath being adapted for insertion into a tissue puncture; a tissue puncture closure device, said tissue puncture closure device being adapted for partial insertion into the procedural sheath and sealing of the tissue puncture; a sheath adapter configured for use between the tissue puncture closure device and the procedural sheath, the sheath adapter comprising: a sheath connection portion positioned at a distal end of the sheath adapter, the sheath connection portion configured to releasably mount the sheath adapter to the procedural sheath; a closure device connection portion positioned at a proximal end of the sheath adapter, the closure device connection portion configured to releasably mount the sheath adapter to the tissue puncture closure device, the closure device connection portion having a rear surface with closure device locking apertures (268A, 268B) defined in the rear surface, the closure device locking apertures sized to receive sheath connection members extending from the tissue puncture closure device; and said assembly characterised in that the sheath adapter further comprises an aperture defined in the rear surface and sized for passage of a carrier tube of the tissue puncture closure device through the sheath adapter. a procedural sheath, said procedural sheath being adapted for insertion into a tissue puncture; a tissue puncture closure device, said tissue puncture closure device being adapted for partial insertion into the procedural sheath and sealing of the tissue puncture; a sheath adapter configured for use between the tissue puncture closure device and the procedural sheath, the sheath adapter comprising: a sheath connection portion positioned at a distal end of the sheath adapter, the sheath connection portion configured to releasably mount the sheath adapter to the procedural sheath; a closure device connection portion positioned at a proximal end of the sheath adapter, the closure device connection portion configured to releasably mount the sheath adapter to the tissue puncture closure device, the closure device connection portion having a rear surface with closure device locking apertures (268A, 268B) defined in the rear surface, the closure device locking apertures sized to receive sheath connection members extending from the tissue puncture closure device; and a sheath connection portion positioned at a distal end of the sheath adapter, the sheath connection portion configured to releasably mount the sheath adapter to the procedural sheath; a closure device connection portion positioned at a proximal end of the sheath adapter, the closure device connection portion configured to releasably mount the sheath adapter to the tissue puncture closure device, the closure device connection portion having a rear surface with closure device locking apertures (268A, 268B) defined in the rear surface, the closure device locking apertures sized to receive sheath connection members extending from the tissue puncture closure device; and said assembly characterised in that the sheath adapter further comprises an aperture defined in the rear surface and sized for passage of a carrier tube of the tissue puncture closure device through the sheath adapter.