Zen tube filters are characterized as one of the favorite brands of tubes for their quality and taste. They come with a tube of king size with a 17 mm filter length. Available in Buitrago Cigars at an excellent price. Zen tube filters are characterized as one of the favorite brands of tubes for their quality and taste. They come with a tube of king size with a 17 mm filter length. Available in Buitrago Cigars at an excellent price.