Contemporary, Exclusive, Modern, Square, Square turned, Stop Chamfer, Traditional Collection Base rail 4200mm 4200x25x66mm This quality 4200mm x 25mm x 66mm length of base rail is suitable for building a staircase with almost any design. The infill is included – this is either 41 mm or 46 mm to match the appropriate spindles’ ranges. It is very important to specify the infill dimension. Please leave us an order note about this when you checkout. The base rail comes unfinished and can be finished by either painting, varnishing or waxing.