Complete overlap curtain kits with all the mechanical parts you need to assemble the rails and pulley system. Detailed instructions are included with the kits, so anyone that is reasonably mechanically minded can assemble these systems.When calculating the overall length of track you need, allow for the curtains to clear the proscenium opening when in the off stage storage position, behind the proscenium arch. You can estimate the required length of track by adding the width of the proscenium opening to an estimate of the bunched up width of the curtain. If you allow 4cm per curtain runner (general runner spacing 300mm), then you will arrive at the correct length. Valance shown in the picture is an optional extra.