Adventures | Warranty / Returns | FAQs | About / Contact | |

Zpacks™ Arc Backpack Frame Components


Our patented Arc Backpack frame consists of two vertical rods and three horizontal bars. The frame rods can be flexed under tension to provide an air gap against the user's back for ventilation and cushioning.

These frame parts are made available for DIY backpack projects for personal use, not for resale.

Our Flexed Arc Frame is is covered by US Patent No. 9,060,590.


Detailed instructions for building our Arc backpack are not available. You'll have to figure out your own DIY design. Here are some pointers.

The vertical rods will need some type of pocket at the top and bottom to secure them to the backpack. We use 1" nylon webbing with aluminum flashing sandwiched inside for durability. Aluminum from a soda can might work.

We use a "mesh back panel" with 11mm polyester webbing to arch the vertical rods. The mesh back panel attaches to 1/2" ladder loc buckles at the top or bottom and can be adjusted to control the amount of arc in the frame. A mesh back panel is available below, ladder locs are sold separately. Webbing, buckles, and other plastic parts are available on our Materials page.

We attach our belt to a horizontal bar at the base of the backpack for improved load transfer. You could sew your belt directly to the backpack and only use two horizontal bars (middle and upper) if you wish to simplify your project.

The Arc backpack design is kind of complicated and may take a few attempts of trial and error to get everything right. You might consider just buying a backpack.


We have different length vertical rods available corresponding to our Arc backpack torso heights. Please consult the sizing instructions on our Arc Blast Backpack page to determine which size you need. They can be cut with a hack saw or rotary saw.
Extra Short 17.5" (44.5 cm) Vertical Arc Stay (Arc Scout backpack) .55 ounces (16 grams)

Short 19" (48.3 cm) Vertical Arc Stay  /  $5  /  .6 ounces (17 grams)

Medium 21.5" (54.6 cm) Vertical Arc Stay /  $5  /  .7 ounces (20 grams)

Tall 24" (61 cm) Vertical Arc Stay /  $5  /  .8 ounces (23 grams)

10.5" (26.7 cm) Flat Horizontal Arc Bar /  $5  /  .3 ounces (8 grams)

Mesh Back Panel / $15  /  .7 ounces (20 grams)