The listing is for one Pilot 3/8" (9.5mm) top dia. for valve seat cutting systems,.274" (6.95mm) stem dia.
Precision ground between centers, hardened tool steel, tapered transition from small to large dia. for structural strength to reduce flexing, cone head for those using "Dead pilot" cutting systems to facilitate quick alignment, 5/32" hole to ease insertion & extraction. supplied with very minimum tapered stem (.001"X3")