The Cheech & Chong glass nail is an essential part of any Cheech & Chong oil rig. This glass part supports the glass dome and carries the concentrates full of stoney goodness. The nail is made of glass so no one will blame you if you accidentally break one. Luckily a glass replacement nail heals any trauma. Remember that the nail and dome go together and that the rig will allow for some movement of the nail. This is perfectly normal.