I have both of them and I prefer the Calypso 2 because of the lengthened bullet and the wavy shape. The Calypso 1 has a ribbed design on the bullet which I didn't really find noticeable while in play, but with the wavy design on the Calypso 2, it lays nicely on top of the pussy for a nice teasing vibration or the head is great for stimulating the clit or teasing the vaginal opening. It is waterproof so you can use it for insertion, but I have always been a little weary of using a corded bullet for insertion. less