CGGA005 Scalextric Guide Post Repair / Adapter - 1/16''
CG Slotcars Guide Repair / Adapter kit includes three (3) 1/16" thick adapters. 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)!!