is dual chain wireless card equal to MIMO?

i was reading about rb751u-2hnd
http://wiki.mikrotik.com/wiki/Manual:Product_Naming


but it does not talk about mimo

number_of_chains
(not used) - single chain
D - dual chain
T - triple chain

The brochure says dual chain 2x2 MIMO.

http://i.mt.lv/routerboard/files/rb751U-2HnD.pdf

thxs for the reply
what is triple chain?

3x3 mimo.

please can you give me some more tech specs?
how much faster than 2x2?
how many band does it use?
5ghz and 2.4ghz?
etc

thank you in advance

Can you use Google and read some general articles about wifi standards?