This brush is one of my more recent purchases and yet it has become a firm favourite in the few weeks I have owned it. So far I have found a few uses and I'm sure I will find more (and in which case this review will be updated).

It is designed as a cheek and highlight brush and is medium sized with soft, fluffy bristles. It has tapered sides that look similar to those of a kite, just softer and more rounded. It is made from cruelty natural goat hair and is hand assembled for quality.
When you first purcahse this brush it is much slimmer and sleeker than once you have used and washed it and at it's fluffiest it measures just under 35mm high and 25mm wide so it's great for smaller faces / cheeks.
It retails for £24.47.

~ First and foremost I use this for contouring my cheekbones. The slim, tall shape means it easily fits into the hollows of my cheeks whilst the tapered edges diffuse and blend the powder as it applies, making application quick and easy. Simply dip the tip and side of the brush into your contouring shade before sweeping it wherever on your face you want to define.

~ It also works well for simple, everyday blush. Wether you like a fresh, rosy finish by applying it to the apples only, or extending it towards the hairline this brush can do it all. It also applies shimmery blushes well, without depositing too much. You can use the tip of the head to buff the edges when you're done if needed.

~ I use the #165 quite frequently for highlighting. Some of my other brushes apply too much product and too much shimmer can look greasy or oily on my face so I'm glad I have found this brush. The sides pick up just enough shimmer to look natural and glowy which gets a thumbs up from me!
I like to highlight the tops of my cheekbones, down the bridge of my nose and above my browbone and this is the perfect size to do all of them. :-)

~ It also applies powder under the eye effectively without smudging or dislodging the concealer below it. I find some denser and rougher brushes do not work well for me in this delicate area but this one definately does!

~ In a pinch it could also apply powder foundation all over the face.

Overall, I'm really loving this brush. If I didn't already own too many powder brushes I'd consider buying another. So many uses, super soft (so great for sensitive skins) and a great new shape. It's also incredibly easy to get the hang of so for all these reasons I recommend it :-)
Though there are probably tons of brushes that could do the #165's job so maybe take a look at them at the MAC store or counter to decide which will work best for you.