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Reviews > Packs > Frameless Backpacks and Day Packs > Gregory Reactor Daypack > Owner Review by Kristine Mar

Gregory Ultralight Reactor Daypack (’08)

Owner Review by Kristine Mar


Biographical Information


Name:  Kristine Mar
Age:     44
Gender:  Female
Height:  5’3” (1.6 m)
Weight:  120 Pounds (54 kg)
Email address:
City, State, Country: New York, New York, U.S.A.
Date:  October 6, 2009


My love for the outdoors began about ten years ago, while I was living in Northern California.  Most of my hiking experience includes day hikes, with an occasional 2-3 day backpacking trip.  I’d consider myself a 3-season hiker and generally like to keep my pack as light as reasonably possible without spending a fortune.  In 2007, I moved to New York City and have enjoyed East Coast hiking and experiencing the outdoors with four seasons.   I enjoy trail hiking in all terrains, and have been fortunate enough to hike in a number of national and state parks, and several countries.



Product Information:


Manufacturer:  Gregory Packs
Year of Manufacture:  2008

Manufacturer’s Website:

Color:  Navy /Grey

Material:  Silicon-impregnated nylon

Approximate volume:  700 cubic inches / 11 liters

Number of pockets:  3+ main compartment
Listed weight:  N/A

Actual weight:  21.6 oz (612 g)




Product Description:


The Gregory Reactor is a small day pack marketed for day hikes, trail running, or bike rides.  The pack is made of a silicon-impregnated nylon which stretches when under pressure.  There are two mesh side pockets for snacks or water bottles.  Each mesh side pockets is large enough for a 500 ml (16 oz) water bottle.  I generally store my pocket knife, headlamp, and a bandana in these side pockets.  There is an internal pocket inside the main compartment which is large enough for a 3 L (100 fl oz) hydration pack.  In addition to my water, the main compartment is large enough to fit a small first aid kit, knit hat, gloves, packable rain pants, a lightweight fleece, a pair of binoculars, and my lunch, which usually consists of a sandwich, fruit, and snacks.  There is a second smaller zippered compartment and a mesh pouch on the front to store items which can be easily accessed.  This second zippered compartment is where I usually store my wallet, cell phone, keys, compass, sunglasses, and sunscreen.  The outer compartment has a buckle closure.  On hot days when I need to take a layer off, I usually roll up a long sleeved base layer and stuff it in this pouch.


The straps on the pack have several elastic bands down each side to string the hose of the hydration bladder through.  The zippers on the pack are plastic and the pulls have a cord with a plastic cap at the end. 


The pack has a chest strap and a waist belt containing two additional zippered compartments for storing small items.  I can fit my digital camera into one side of the pouch, and I generally keep my lip balm, along with dried fruit, trail mix, or an energy bar in the other pouch.  The back panel uses Gregory’s Aero-Tech™ mesh technology which allows for breathability and helps move moisture away from the body to keep me dry.  There are two side and one front compression straps and a gear loop.  The pack also has a reflective tape down the center for better visibility.



Field Information


I have used this daypack more than 30 times on day hikes ranging from easy, moderate to difficult throughout New York State, New Hampshire and Connecticut.  The hikes ranged from 2 hours to 10 hours, covering distances between 4 miles (6 km) and 15 miles (24 km) and elevation gains from 400’ (122 m) to over 4000’ (1,219 m) scrambles. 



Field Experience


When I was looking to purchase a daypack important factors were:  the size, the weight, internal water bladder, and appropriate air ventilation on the back panel.  Being a 5’3” (1.6 m), 120 lb. (54 kg) woman, I wanted something that was lightweight, which molded to my back, and yet provided adequate ventilation for those long, hard climbs.  I was previously using a backpack which was 1200 cu in. (20 L) and I initially thought that 700 cu in. (11 L) might be a bit small.  However, this pack is nicely designed and has all the features I was looking for.


The pack is adequate for spring/summer/fall day hikes in the northeast.  I am able to fit a 3 L (100 fl oz) Platypus bladder in the pack, with my lunch (which generally includes a sandwich, 1-2 pieces of fruit, and snacks – trail mix and/or energy bars).  In addition, I almost always carry a small emergency first aid kit, a headlamp, gloves, hat, and packable and waterproof pants and shell.  I generally am able to fit another long sleeve t-shirt or fleece either inside the pack or tied to the outside as another additional layer depending on the weather conditions.  A few other things I always have with me are a multi-purpose pocket knife, wallet, cell phone, camera, lip balm, sunglasses, sunscreen and keys and all this seems to fit into the pack with no problem.  Sometimes, I even bring a small pair of binoculars and hiking poles which I attach to the outside.


I have used the pack mainly for day hikes on maintained trails, in the northeast in the states of New York, Connecticut and New Hampshire.  A few of the more challenging trails included steep ascents, and some bouldering.  The Gregory Reactor works great for trail hiking.  It fits snugly to the body, and the weight is distributed evenly, so the pack becomes barely noticeable.  I have also tried using this pack for snow shoeing, but found that the pack was a bit small for the gear required for winter activities which include, heavier extra layers, thicker gloves, and additional socks.  I also found that drinking water from a hydration bladder was not ideal during the winter, since the water freezes in the hose.


The positive aspects of this daypack are:  the pack is extremely lightweight and fits my body perfectly.  The mesh back panel back works well to keep the moisture away, and surprisingly I am able to get all the things that I need into this daypack.  The zippered mesh panels on the waist belt are also a brilliant addition.  I have a digital camera that is on the large size, and although it is a tight squeeze, I am able to fit my camera in here so it is always handy in a case wildlife suddenly appears.  I also keep lip balm and a snack in the waist belt for easy access.  This backpack has served all my needs for active pursuits and was exactly what I was looking for in a daypack.  I was concerned about the thinness of the fabric initially, but so far, it has held up well, with no problem.  I can climb steep ascents, and barely know that the pack is there.  It is so comfortable.


The zippers and pulls on the packs are well designed.  At first, it seemed that the nylon fabric the pack is made of would easily catch on the zipper, but this has happened only on rare occasions when I was not paying attention.  The zippers work as well today, as when I first purchased the pack.  I have had other packs where the pulls which were made of leather disintegrated and the zippers slowly became more and more difficult to operate from normal wear.


The only negative aspect of the pack is that due to its technical design, it is a little small for everyday use, travel, and winter activities, so it is not versatile in that respect.  I find that during the winter season, I have difficulty fitting a heavier fleece into the pack, and if I get hot from snow shoeing, I have to tie my waterproof outer shell to the outside of the pack.  I also cannot fit snow gloves into the pack and usually end up clipping them to my pants or jacket.  This pack is also too small to use for travel as it will not fit or have the padded support for a laptop computer.  There also seems to be a lot of straps, but I find that I have this issue with most technical packs.  The positive aspects of this lightweight daypack far outweigh the negatives.


The Gregory Reactor is a lightweight daypack, which comfortably carries my gear and is barely noticeable on my back during active pursuits.





1.     Lightweight

2.     Hydration compatible

3.     Aero Tech mesh back panel

4.     Zippered mesh panels on waist belt





1. The size does have some limits.

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Reviews > Packs > Frameless Backpacks and Day Packs > Gregory Reactor Daypack > Owner Review by Kristine Mar

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