PVC Extrusion for Channel Frame, Black. Dimensions 21mm H x 8mm D x 2400mm W. In conjuction with othjer components,i.e. 'H'-Extrusion and Corner Joiners it is possible to create custom size frames up to 2400mm x 2400mm. Ready-made Channel Frames ara available in sizes A0 to A4. Two lengths of the I-Extrusion required for the media loading side. (Simple assembly required).