The Studiospares Airpump Support drastically reduces issues with mounting heavy PA Speakers on stands. Utilising an air-cushion to suspend the speaker on a column of air, they can take extremely heavy speakers with ease. The leg support assembly is metal, not plastic, the pole locking mechanism is non marring and consists of a conventional clutch backed up with a retained safety pin passing through the pole. The height is adjustable between 1.2m and 2.2m. The maximum load is 60kg. Upper pole diameter is 35mm. On a price to performance basis alone, this product comes second to none.