Question 1

will this work with a t430?

Accepted Answer

I bought this dock from NewEgg and it works fine with a T430s -- my understanding is that the T430 has same docking interface as the "s" model.

Question 2

How many of these do you have?

Accepted Answer

If you are asking how many are for sale, I don't know.

I, personally, have one. I use it in my office with a Lenovo T430 and attached it to  an Ethernet cable, a 3.0 USB hub, two external storage devices, a wired mouse and wireless keyboard, a monitor, a speaker system, an external burner, and a television. And of course, the power cord for it. I love it.  I set mine up to model what the teachers in my area use in their classrooms. 
I don't know how I ever did without it.

Question 3

Is this product compatible with a T420s?

Accepted Answer

according to download.lenovoDOTcom(slash)ibmdl(slash)pub(slash)pc(slash)pccbbs(slash)options_iso(slash)ocm_march_2014.xlsx

(on the "TP T" sheet)

Shows compatibility with: T530, T431s, T430s, T430, T430u, T520, T420s, T420, T510, T410s, T410 and T400.

Question 4

what models is this compatible with?

Accepted Answer

ThinkPad Mini Dock Plus Series 3 with USB 3.0 – 90W (433815U - U.S.)is compatible with:
L412, L420, L430, L512, L520, L530, T400s, T410, T410i, T410s, T410si, T420, T420i, T420s, T420si, T430, T430i, T430s, T430si, T510, T510i, T520 Dual Core models, T520i Dual Core models, T530, T530i, X220, X230, X230i

Question 5

Will this add USB 3.0 functionality to a Lenovo T420 i5-2520QM?

Accepted Answer

I have this dock and use it with a T430s, but don't specifically know the answer to your USB question. As the dock has no software or intelligence on board, I would think it is simply an extension of whatever functionality is already present on your laptop.

Questions & Answers