This is the Wizard's Sleeve.
It is actually two sleeves.
It quickly links a paddle blade with a karabiner to
make a paddle hook.
The main sleeve wraps around the blade held tight with
red velcro. It is adjustable for different blade sizes.
The micro sleeve holds the HMS karabiner firmly in place and offset from the blade edge to give more stability. The yellow stitching indicates the leading edge & creates the offset for the karabiner.