The Elements 107mm Optimo Lens Hood is required to use filtration for 107mm rounds. The new O.D. of the hood is 110.5mm, smaller than the stock hood. The factory hood must be removed before this filtration hood can be installed.
The original hood is mounted to the lens with a high strength thread locking compound. This bond can only break with heat. A heat gun is the best device for delivery and control of the heat however care must be taken not to overheat the interior of the lens assembly.