The TERADOWEL and ULTRADOWEL systems comprise discrete steel-plate dowel and plastic release sleeves. The sleeve contains nails for fixing to the timber formwork and the dowel slot is covered by tape to prevent cement paste entering when the concrete is poured. The inner bracings in the sleeve prevent deformation or collapse of the horizontal sleeve walls caused by the concrete pressure in deep slabs and allow problem-free insertion of the dowel into the sleeve after formwork stripping.