CGGA07 CG Slotcars Scalextric Guide Post Repair / Adapter, Combo
CG Slotcars Guide Repair / Adapter Combo kit includes three (3) adapters - one (1) each in 1/32", 1/16" and 3/32" thickness. Existing guide needs to be drilled out @ 3/16th (4.8mm) and these fit right in to accept most major brands of guides (e.g. Slot.it, Sloting Plus, Scaleauto, etc.).
See this great installation article on HRW (Home Racing World)!!