Sephora retractable brush is an excellent travel-size powder brush that will easily fit in your make-up bag. It's elegantly packed in a black metal case, which after opening reveals a thick, dense brush you can use to apply pressed or loose powder. The bristles are a bit on the hard and pricky side, they tend to scratch pressed powders and are not that nice and soft to touch. Nonetheless, if you use this brush for touch ups on the go, not as your basic make-up tool, this makes an excellent choice. Priced at around £12 this is not the cheapest option, but it's definitely worth giving a go.
Sephora retractable powder brush
Disclaimer: I bought the product myself for my personal use and I am not affiliated with any company. I am not paid to do this review and everything I said here is my genuine opinion.