All tubes have light smoke in technological windows. This effect is not visible while the tube working.Tubes come in this condition from the factory, looks like appear after burning air. For more details please check the last picture. You will receive what you see. The item "6x IN18 IN-18 -18 NIXIE TUBES NOS NEW TESTED MATCHED SET Meter Clock" is in sale since Wednesday, August 11, 2021. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets". The seller is "ukrainian_gifts" and is located in Kyiv. This item can be shipped worldwide.