Not all GH is equal. Making GH is a very complex task and the resulting product can be higher or lower quality. Naps or any source you use that sells generics, will often mark the GH they have with colored caps to differentiate quality. So thats not to say that a cheaper GH is garbage. It just might not be quite as good as the next level up. One thing to note is that anyone can put any colored cap on a vial so just becuase Naps has gray top that you like, doesnt mean that another source's gray tops are the same thing. So a colored top might tell you the level of quality from one source, but that color coding system is not going to be universal. Another source can slap a grap top on a lower quality GH and sell them for, lets say $20 less than Naps. Does not mean that is a good deal just because the cap is gray