Set of 3 OEM Piaggio Standard Variator Sliders or Siiding Blocks for Vespa 150-200, Aprilia 125-200, Piaggio 125-200 with Leader Engine. 4348555. Also called Variator  Guides or Guide Shoes or horseshoes. 

These have been made by various companies over the years and  come in shades from almost white to dull yellow to flourescent yellow. They are interchangeable with the variator slides for the GTS and GTV that are green.