Nikor made 2 similar 4.5-inch diameter tanks: the 4x5 reel is designed to fit the 4.7-inch tall tank, and two 220 film reels (the larger 4.5-inch diameter reels) fit the taller 5.6-inch tall tank.

The Nikor tanks with the smaller stainless steel cap were designed for inversion. But in practice, I find I must hold the cap on tightly during inversion.