The Tacco Elastic Arch Support 650 has a thin medium height semi rigid plastic support piece that is covered with a genuine leather top cover for added comfort. What really makes Tacco Elastic arch supports somewhat unique is that they are one of the only reasonably priced arch supports that has a built in metatarsal arch. This means that Tacco Elastic arch support provides support to the medial lateral and metatarsal arch. The metatarsal arch is created from a firm triangular shaped foam pad that is glued to the top of the plastic arch support (but underneath the leather cover). They have a small donut hole centered in the heel of the plastic arch. This hole has a cushion plug that fills it and protrudes out the top and bottom. The foam plug and the donut hole make the heel feel softer and more cushioned. Also Under the heel there is an adhesive pad that can be used to keep the arch supports in place in sandals and open heel shoes.