Once you have removed the pillion footrests, fill the void left behind and cover those otherwise exposed holes in the sub-frame with the R&G blanking plates. 

This pair of Footrest Blanking Plates have been specially designed to cover/protect both side of the Zero FX '19- .

R&G Footrest Blanking Plates are easy to install, simply screwing into place in-place of the rear pillion pegs, covering those otherwise exposed sub-frame holes, that if left uncovered could result in corrosion of the frame/subframe from dirt, water and debris buildup.