<http://schema.org/description>
"A pair of clamp plates with screws to join two fixed rails together by clamping across the junction on the upper guide, using holes provided in the rail. IMPORTANT: the junction must always be supported by a rail-mounting bracket placed astride."^^<http://www.w3.org/2001/XMLSchema#string>
<https://www.manfrotto.us/rail-connector>