IMHO sliders are those triangle-shaped items which allow your CVT plate to "slide" up and down its guidings. Please anyone correct me if I mx up technical specs.
I think they are sold because they will carry the belt slightly higher and slightly lower on the pulley face, than does a barrel shaped roller weight.
Playing with the weights of the Dr P. "sliders" will increase top speed, or increase acceleration --- and some claim the 'right' new weight will do both*! Playing with roller weights will do the same....up here, down there - vice-versa.
* One can only puzzle about why the technicians at Kymco or Honda or Vespa or Suzuki hasn't discovered these magic weights?!
Stig