Easton 4mm Aluminum Half Out Inserts - Size #2, 12pk - Easton’s 4mm Aluminum Half-Out Aluminum inserts enable the use of common 8-32 thread broadheads in 4mm Full Metal Jacket and 4mm Carbon Injexion shafts. Precision machined from aluminum, this half-out delivers high strength-to-weight ratio. The package contains one dozen (12) 35 grain half-out inserts.