For your French oil lamp! If your lamp is only equipped with a chimney and you want to add a shade to your oil lamp then this is what you need. This slides over your burner. The outside is approx. Ø 2 29/32″ or 7,4 cm wide and the inside is approx. Ø 2 9/32″ or 5,8 cm wide. Used item, signs of use.