Danielwrote a review of Blackburn Outpost Wrap Bag on May 20, 2018
Familiarity: I've used it several times
I had high hopes for this bag - it seems like a perfect idea to put my flat kit in and keep it down low on the downtube out of the way. In practice it's not so great.
Number one - it only works well with fairly flat items. Once you roll it up anything bulky (tube, little sealant bottle, bulky tire levers, etc) turns this into a giant burrito that slides around doesn't secure well. The internal divided storage is all fairly small compartments so it doesn't fit everything I want to bring.
Number two - it doesn't seal well. If you put it anywhere on the bike that gets hit with dust or road spray expect things inside the roll to be coated.
Number three - it's hard to attach. The attached Velcro straps fit many frame shapes but they are fussy to undo and redo quickly on the side of the road. The zip off wallet does not zip off or on quickly.
This kit might work for you if you want to carry flat items like a medical kit. Prepare to pack it minimally and mount it in a place that doesn't get too dirty. It doesn't work for me.