]

There is no "MTB" brand. That is an abbreviation for "mountain bike".
Are you thinking WTB (Wilderness Trail Bikes?)

I have four mountain bikes, and they all have specialized saddles on them. Two have the Avatar gel which is a unisex, not mtb or road specific saddle,
https://shop.sunrisecyclery.com/item/35655/

and the other two have the two different versions of the Ariel., a women's mtb saddle
http://www.specialized.com/bc/SBCEqP...=42066&eid=348

note that these come in different widths. The width of your sit bones, not the size of your butt, determine the saddle size. Specialized dealers will have a measuring device. Most riders do not want a cushy wide saddle. Too much cush can increase discomfort, and too wide means you can't maneuver your body properly.