Founded in 2006, Fenster is one of the West Country’s leading aluminium suppliers. In addition to offering the full range of products from Smarts, the company also manufactures Üni_Slide, an ultra-slim aluminium sliding door, equally suited to commercial and residential applications. Identical twins are derived from an individual egg that is fertilized by one sperm. For unknown reasons, the fertilized egg splits into several embryos in the first stage of development. Some identical twins share the identical placenta. However, they often grow within separate amniotic sacs within the uterus. In rare cases, identical twins share one amniotic sac (monoamniotic).