This collar helps to protect the hickory haft of splitting and felling axes and hatchets in the event of an over strike. If you've ever seen an axe that's seen any real use you'll notice chips and gouges out of the handle just under the bit. Even the most accurate woodsman will over strike their mark form time to time, leading to premature wear on the handle in a critical area.
This overstrike guard will fit most common outdoor axe handles.