my feather duster's tube is (or was when I got him) about 6 inches total in length... it stays in the substrate and has about 1 1/2 inches of the tube sticking out of the sand (straight up) the other 4 1/2 inches (maybe more now) is buried in the substrate.... it seems very happy with a very good looking crown... he never shed the crown or moved from the spot i put him in... I did not bury any of him in the sand, he did it himself... Ive had him for over 10 months.