Length

I use a two inch tube,my cock is getting thicker now I want more length,I was thinking that a 1.75inch tube would be okay for this.

Why only tubes ? Stretching and other methods can also help you gain length.

Yes do some nice stretching and hanging but only if you’re trained enough!

I’m assuming you’re talking about pumping.

Generally, thinner tubes are better for length, since it shouldn’t put as much ‘lateral’ strain on your penis. It’s also good to use plenty of lubricant so that the penis can advance along the tube more easily.

I used a 1.75 inch tube before, it worked ok. I used the kaplan pump.