One size fits most because of how the openwork pattern stretches. I had a trunk show and saw this piece on many body types; it looked great on all of them. The bolero uses one skein of Magnum and #17 & #19 needles, straight or circulars since the piece is worked flat.

I would rate this as an easy pattern for an intermediate knitter and a bit of a challenge for a beginning knitter. I’ve manipulated this particular openwork pattern a bit to where I think it might throw off a knitter not solid in their skills. It is a quick knit though, a couple of nights work tops.