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 Aprilia RS660/ Tuono 660 '21-'24 (PAIR)
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.