The purpose of the Plastmaster is to stop the damage done to plasterboard when installing or removing downlights, as it creates a solid surrounding edge once plastered in.
Plastmaster is made of ABS heat resistant plastic capable of withstanding temperatures to over 100 degrees. It is suitable for installing in 9.5 mil and 12.5 plasterboard.
Each Plastmaster mould comes in various sizes to suit all size of downlights. The cut-out size of each Plastmaster is 86 mil , I would suggest a maximum of 10mm cut out of the downlight below the size of the Plastmaster.