Thes are the gloves that wannies use in the mine of the Island of the Wannies. It protects the user's hand from fireballs or lava. The glove doesn't do any damage by itself, but Twinsen can use the glove to deflect fireballs thrown at him, and can direct them back to the enemies
The glove can be found in the mines or in a house in the Village of the Wannies. It is necessary for getting the fragment of the mosquibees, because the key to the chest where it is held is dropped by a gas monster that appears at the arena. In the arena, the only way tu hurt the monster is by throwing back to him the fireballs he shoots.
"With this Wannie's glove, you can now touch the fire. This will allow you to throw back the fireballs that the monsters from the gas hurl at you."