Tissue culture-treated inserts are designed for use with horizontal and vertical diffusion chambers. The Snapwella? insert is a modified TranswellA insert which contains a polycarbonate or clear polyester membrane supported by a detachable ring. The membrane is housed in a two-piece polystyrene assembly. Snapwella? inserts snap into place. Snapwella? inserts are supplied preloaded into 6-well plates.