Harmer Modulock deck supports allows you to adjust the height of paving slabs, timber or plywood sheet decking to level out irregular, uneven or sloping surfaces so the spaces are more usable. Harmer Modulock is a raised pedestal system which also lends itself to concealed drainage, pipework, and services beneath a substrate and application for terraces, walkways, balconies and ballasted flat roofs. Complete with self-levelling heads that allow for a 5% gradient change, the heads have anti-noise and anti-slip rubber layers on their heads. Using Harmer Modulock deck supports to adjust the levelling of surfaces is extremely easy. Each deck support features four 12mm x 4mm tabs to ensure an even alignment of paving slabs, timber or decking. There are 14 basic modules so you can adjust height from voids of 37.5mm to 550mm with couplers enabling you to achieve a wide range of heights from one product. This specific Modulock deck support will adjust voids from 300mm “ 400mm and comes with 2 extension couplers so you get a wider range of height adjustment. Simply tighten or loosen the extension couplers on the plastic threaded rod to change the height. Resistant to temperatures from -40C to 120C, Harmer Modulock deck supports are manufactured to be resistant to acids and mould thanks in part to their UV stable polypropylene components. Harmer Modulock Deck Support Properties Height Adjustment: 300mm - 400mmExtension Couplers: 2