Dbl. Edge Ring
"Sword damage ^ but you get hurt"
The Dbl. Edged Ring is a Magical Ring that Link can obtain in Oracle of Seasons and Oracle of Ages. Link can acquire the ring by planting a Gasha Seed and finding it within a Gasha Nut. He can also acquire it in a Seed Ring form by bumping into Maple. The ring can also be obtained through a Fortune Link at Vasu's jewelry store.
When equipped, the Dbl. Edged Ring will significantly increase the damage done by Link's sword. However, each successful hit will cost Link a full Heart Container in damage. There is very few practical uses for the Dbl. Edged Ring, as other power based rings such as the Power Ring L-3 or the Red Ring are much more effective.
Trivia
The Oracle of Seasons and Ages Nintendo Power Guide refers to this ring as the Razor Ring.