Flexible connection between tracks; possible to connect tracks at an angle sideways or up/down where the ceiling height differs. http://www.ikea.com/th/en/images/products/ikea-sanda-connector-with-flexible-joint__0089924_PE223233_S4.JPGIKEA 365+ SÄNDA Connector with flexible jointhttp://www.ikea.com/th/en/catalog/products/50131697/501.316.97300 THB