Mira Flight Low Rectangular 'Easy Plumb' Riser Kit 1200mm. 1x Mira Flight Rectangular 'Easy Plumb' Riser Kit 1200mm. Shower Tray Panel Riser Kit Square/Rectangle Trays 1200mm Plinth Adjustable Feet. Increase the height of your shower tray with the Mira Flight Low Easy Plumb Riser Kit.