This is a Glow Plug Die from Higley.

FEATURES: Has the uncommon 1/4-32 thread used on glow plugs Made by the USA's largest threading tool manufacturer Rethreading all glow plugs with this die eliminates the chance of installing an improperly threaded plug and ruining your engine's head.

INCLUDES: One Glow Plug Die

SPECS: Thread Pattern: 1/4-32 ir/kh  

BOX DIMENSIONS: 4.00" W. X .50" H. X 4.00" L. BOX WEIGHT: .07 LBS.