A bonnet insulator is useful for a number of reasons. It helps to reflect heat away from your bonnet and back into your engine bay (helping to prevent cosmetic damage to the bonnet's paintwork that can be caused in excessively hot conditions) and it can also help to reduce engine noise emanating from the engine bay.
In most markets, the 2018+ Jimny was supplied without a bonnet insulator and so it has become quite common for customers to install aftermarket examples.
This Bonnet Insulator is secured using the supplied clips that fit inside holes that are already present on the underside of the Jimny's bonnet. No drilling or cutting is required and no permanent modifications are required to be made during the installation.