This Auction is for a stainless steel adapter. 

(3/8"-16 Male by  8mm -1.25 Male)  Stock OD is 1/2" .  Part B2409-20

This 1/2" diameter adapter for thread conversion  

  • Typically used on pole spears and with other manufacturer spear tips 
  • Flats for 7/16" Wrench
  • Can be used for other applications too