Rubber stamps are approx. 1/4" tall and are available as un-mounted only, mounting foam is available for diy. These foams are thin mounts (1/16") so are easy to cut letters out with a sharp Exacto blade or good scissors.
 
2-sided adhesive foam for permanent mounting (for wood mounts)
1 side adhesive 1 side cling mount (for use with acrylic mounts)
Also available as a single wood mount (on request)