Each extension has a shootbolt, in addition the 840-1150mm and 1100-1410mm extensions have a roller cam per extension.
Please measure the total length in mm when all three pieces are put together on the upvc window then select the correct size range that your measurement fits into.
We will then send you the correct size range extensions to be cut down to the exact size by yourself.
Sash Rebate: The total length of the opening window where the extensions are fitted.
These extensions are sold in pairs. The price shown is for a pair.