Yes, it is a remote. You do not need to get the fairly expensive Canon one either, for a lot of other makers sell wireless shutter releases that will fit your t2i and only set you back $50 or so.
The key is NOTHING can move at all on, or IN the camera, so a very sturdy tripod is mandatory.
The other external motion-creating device on a camera, even on a sturdy tripod, is the photographer's "booger" finger! LOL. No matter how gentle you think you are, your finger depressing the shutter button WILL cause a slight blur that otherwise would not happen on your images. BAD especially with long shutter speeds but really, unacceptable at any shutter speed if you want crisp photos!
NOW . . . LETS "DAMP" THE INTERNAL VIBRATIONS!
Camera timers are "ok" I guess . . . but the old internal mirror is still banging around when you use the timer mode. There's a much better way. Read on . . .
Looking through the eyepiece of any SLR, you will see an image thanks to a mirror that reflects the image through the lens onto that mirror so you can see it. However, that mirror always has to flip out of the way so the shutter can fire . . . and that mirror is gonna cause a little vibration when it snaps up and down!
SO . . . "MIRROR LOCK UP" (or in the terminology used on the t21) . . . "LIVE VIEW" is your friend. In live view the mirror clicks out of the way and STAYS out of the way and you get a "video" image on your back screen since the eyepiece viewer now has no image with the mirror locked up. You have to also put your camera on manual focus and focus using the back screen too. Check your manual for how. It is very, very easy to do. It works great on macro and landscape photography too!!!
With the mirror out of the way; your image properly focused manually; your booger finger pushing down on the wireless remote shutter release rather than the camera; and your sturdy tripod keeping the camera rock solid . . . your photos can now be stunning rather than just mediocre.
Yep, if you already have the tripod you are only about $50 bucks from having a different level of images! Hope this helps.
BTW, I use a $50 Satechi wireless remote and it is WONDERFUL for so many types of shooting. Google it and you'll find 'em on Amazon. I can't imagine shooting without it in SO MANY settings.