i started with a 23G 1" and went to a 25G 1.5 for delts...only reason i did this is cuz i ran out of the 23G 1" if i had to choose it would be 23's for me ...the 25 goes in like nothing you dont feel anything at all but the only thing that sux about it is it is hard to inject the liquid through the little pin and it feels like the pin is in you forever because it takes so long go with the 23's bro