Meltzer's dilator set consist of 1,2t,2,3t,3,4. The "T" dilators are tampered and are only used to open up enough room so the non "t" dilator will fit. Mariah and I have found that when you are going up, you would use 1,2t,2 as a set. Net step would be 2,3t,3 as the next step. The reason for this is the small dilator will give you full depth until you can get the larger dilator to full depth. Once the larger dilator will go to full depth, you can discontinue usage of the smaller ones.