I’ve spent a lot of time with my trusty REI Flash 45. I bought it on impulse back in 2015 at the end of the season sale. It was on sale for a whopping $50. I couldn’t have ever expected that the REI Flash 45 would last me three years of backpacking and a thru hike of the Appalachian Trail.
2015 REI Flash 45 Specs
- Weight is listed at 34 ounces.
- Aluminum Frame
- 45L capacity
- Main pocket plus external mesh and top
2017 REI Flash 45 Specs
Weight listed at 44 ounces
- Aluminum Frame
- 45L capacity
- 6 external pockets and the main one
They made a lot of changes to the Flash lines over the recent years, what was once a simple, cheap, and light gear line turned into bloated gear for people with REI gift cards. They added 10 ounces to the weight for not much of anything. Having experienced both the 2015 and 2017 model I can say the 2015 feels like an ultralight pack where the 2017 feels closer to an Osprey or some other heavy duty backpack. The rest of the post is dedicated to the 2015 Flash so if you are interested in buying a new pack then I suggest you head over here and find one!
Modifications to Save Weight
This isn’t just applicable to the Flash 45 but any pack you currently have. First, I cut off all of the extra lengths of straps. This took me roughly an hour after sewing them back together and saved me an ounce. Maybe not worth it, but every ounce counts. In addition to this, I cut the brain completely from the pack and tossed it to the side. Since the pack is already 45L, there is no use for the brain anyway. Removing the brain saved 3.5 ounces. I also ended up removing the frame, since I was using a Thermarest closed cell pad it kept the structure just fine. This saved 4 ounces. Finally, the pack looked like it came out of a backpacking horror movie so I had to cut all the miscalanous straps and other gadgets REI thought I would use off. This saved me another ounce. After all said and done, I have a pack that now weighs 23 ounces and I only paid $50 for it.
If I wanted to take it my pack down even further I would cut the mesh off of the back which I would assume to be another two ounes in savings. I could likely also cut the hip belt off and save up to 3 or 4 ounces. Making the pack weight close to 1 lb.


Why did they change it?
I ask myself this, but from the perspective of REI I bet the design was changed to fit a less niche market and instead mainstream the product. Most backpackers aren’t interested in being ultralight instead they want more convenience. They added this convenience by giving hikers 6 pockets so instead of having to organize their own gear, the pack does it for them. The material of the new REI feels slightly thicker than the old Flash 45 but I cannot find the specs for the material on the 2015 model. If you’re looking into getting an ultralight pack then the Flash is no longer the pack for you.
Head over here to find the best ultralight pack.