Our packing system sacks are sized volumetrically in liters. To help illustrate how those volumes translate to real world use, here are some typical things you might put in various sizes of packing system sacks:

• 2.5L = small personal items, snacks, or a first aid kit
• 5L = a few meals for two, baselayers, or other small essentials
• 10L = a down jacket, food for the weekend, or a small sleeping bag
• 20L = a typical sleeping bag, a couple changes of clothes, or bulkier gear items like a tent or camp kitchen setups
• 30L+ = from 30L and up, most items for an overnight trip can fit into one of these sizes

SealLine products use three ratings to describe water resistance:

• Splashproof: Withstands light rain and splashes. Only some of our products fall into this category. Suitable for use where light water resistance is sufficient, such as summer backpacking.
• Waterproof: Withstands quick submersions. Most of our bags fall into this category and are suitable for canoe, kayak and rafting use where boats may tip, flip or be swamped.
• Submersible: Withstands 1 meter of submersion for 30 minutes (IP-67 standard). Suitable for use in extreme and prolonged wet situations.

With such ratings, water resistance depends on the user carefully and properly sealing the closure. For roll-top closures, this means a minimum of three tight, wrinkle-free rolls. For zipper closures, the zipper must be completely and properly closed.

We recommend a minimum of 3 folds (aka “rolls”) to properly seal a roll-top packing system sack. For an optimal seal:

• a. Make sure the stiff sealing strips are wrinkle-free. Close the packing system sack so that the sealing strips are pressed together
• b. While holding strips together, push down to “burp” out trapped air. Once trapped air has been “burped” out, tightly fold the top over several times so that the roll-top closure has been folded at least 3 times
• c. Connect the buckle in the direction opposite to the direction the material was folded

All of the dimensions we list for our roll-top packing system sacks are the dimensions of the product when it has been properly sealed (tops rolled down three times and secured).

Welded seams use radio frequencies (RF) to join two pieces of coated fabric together at the molecular level, effectively bonding them together as one. This strong, reliably waterproof construction method is far superior to sewn-and-taped seams.

With sewn-and-taped seams, two pieces of coated fabric are held together with thread and a piece of protective tape is placed over the threads and seam to provide water protection. A RF welded seam can withstand up to 2x more stress than a sewn-and-taped seam, resulting in a more protective and longer-lasting seam. This is why we use welded seams with all of our dry bags.

• Dry bags come from the paddlesport world. They are made from heavy-duty materials that withstand the stresses of exposed, demanding use in or around wet, aquatic environments. Dry bags are frequently used by paddlers (e.g., canoe, kayak, raft, SUP), though they are increasingly used on land in circumstances where their durability and protection against the elements are beneficial.
• Packing system sacks come from the camping/backpacking world and are typically made from lightweight or ultralight materials. They are meant to be put inside a larger pack or bag, providing selective water protection and/or organization for specific items (e.g., sleeping bag or clothing) with minimal overall weight penalty.

Regularly cleaning and maintaining your packing system sack will substantially increase its life. After each use, packing system sacks should be cleaned and aired out. Dirty sacks can be washed with a soapy sponge and rinsed, allowing them to air dry. Store clean packing system sacks completely dry, inside out. Keep all insect repellents and solvents from making direct contact with packing system sacks—if contact occurs, wash the sack thoroughly.

These purge valves let you easily vent excess air trapped within a sealed packing systems sack without compromising water protection. Venting trapped air prevents the bag from “ballooning”, helping it compress and save valuable space. We selectively use these valves on products that may frequently be strapped down and/or compressed and stowed in tight spaces.