1) The Mac 242 is a shader brush, it has firm fibres shaped to form a rounded edge. It's great for applying concealer and packing on eyeshadow. I use it to apply my eyeshadow as it packs on an intense layer of colour without any fallout as it's flat. I use one side for one colour, and the other side for another colour. I use the tip of the brush to apply colour to the inner corners, and line my upper and lower lash line.
2) The Jemma Kidd "Deepen" brush is great for getting into the eye socket and applying colour into to the crease. It's made from natural hair, quite small yet firm with a slight tapered tip. It's therefore great for precise application and also fluffy enough to blend. (This particular brush is no longer available as I purchased it as part of a set last year. But, her double ended eye define brush includes it. Price: £14.99
Price: $28 (I purchased mine as part of a set from QVC last year.)
I really recommend you check out the shapes of the brushes, every brand has their own range with great dupes. I have SO many eye brushes that I use on rotation but, I just happen to favour these from my collection. If you have 3 brushes similar to these, you should be able to apply eyeshadow to a professional standard once you get the hang of blending.
Happy blending! :)