Boxer Pro Lunchbox Conversion

Update 2026-07-21: I've uploaded a version 2 that requires fewer cuts in the lunchbox.

Update 2026-02-05: I've added a clip to hold the first link outside the box https://www.printables.com/model/1587049-boxer-pro-belt-clip

There are a number of problems with the hard plastic belt box that comes with the Boxer Pro.

• It has the space to hold about 75 links, so naturally they sell the belts in multiples of 50.

• The latch mechanism is on the inside of the box, which means the belt can get caught up on it.

• The release button would be much more ergonomic if it was mounted “upside down”.

• You can't reload the belt without removing it from the box.

• Dart Zone doesn't sell extra boxes.

You know what solves all of these problems? A lunchbox.

I love MacGyvering things, so I designed a latch that can easily convert a lunchbox to hold Boxer Pro belts. Even small lunchboxes can comfortably hold 100 links. Lunchboxes that unzip from the front allow you to load the belt without needing to remove it from the blaster (or the box). The water bottle pocket (if your lunchbox has one) is the perfect size to hold that little cardboard box of darts the spare belts comes with too.

Need more than 100 links? A slightly larger, top-loading bag can easily fit 200. You can add rigidity to softer bags by sticking in the cardboard box the belts came with (I taped two of those cardboard boxes together for the larger purple bag in the pictures). Do note this becomes comically large, and presents a massive target for blaster tags.

Materials:

• 4x M3 bolts and nuts (length depends on thickness of the lunchbox, but you'll need at least 12mm for the print itself)

• 1x small spring less than 5mm in diameter (for the latch button)

• A lunchbox. I've been using softer, flexible boxes, but there's really no reason this can't work with a hard box too (provided you can cut/drill holes in it)

  • 3.5" x 7.9" x 9.9" is about as small as you can go while still holding 100 links.

Printing:

The parts print best in the orientation shown in the pictures. These are the PrusaSlicer settings I use. I print all of my plates in PETG.

For the top plate,

• 3 Perimeters

• Minimum shell thickness 2mm (top and bottom)

• Enable 5mm brim (so it doesn't fall over while printing)

• 10% gyroid infill

• Enable supports everywhere (Style = Snug, Top contact Z distance = 0.2mm, Top interface layers = 0)

For the bottom plate and latch. The bottom plate will be under some tension, so you really want it to be solid. Use the same settings as the top plate, except:

• Disable brim

• 100% infill

Assembling:

The top and bottom plate essentially sandwich the material at the top of the lunchbox, and the bolts hold it in place (so minimal cutting is required). Please see the attached pictures for reference.

1. Using the bottom plate as a guide, mark the spots for the 4 bolt holes in the top of the lunchbox.

2. Use some kind of sharp tool without a blade to poke through the holes. Resist the urge to use a knife, as the blade will make a cut that wants to keep ripping under force.

3. Version 2 does not need an additional hole for the latch. Version 1 sometimes requires you to cut a small hole for the latch itself. Every lunchbox is a little different.

4. Insert the latch into the top plate.

5. Position the bottom plate inside the lunchbox, under the holes. Put the beveled edges against the fabric (this helps avoid the sharp corner tearing a hole in the fabric). Position the top plate (with the latch installed) above the lunchbox. Loosely secure the rear two holes with bolts.

6. Installing the spring is a bit of an acrobatics act. You kind of need to just wedge it in there (this is why we left the rear bolts loose). The latch has a hole for the spring, and the bottom just sits on the lunchbox material.

7. Loosely install the front two bolts.

8. Gradually tighten all the bolts, going across (like you're drawing a star, or changing a tire). This will help avoid putting too much force on any one corner of the plate.

9. Cut holes for the belt on either side of the plate. The edges should at least be secured with duct tape. I sewed some aesthetically pleasing orange fabric onto mine (from an old t-shirt).

10. (Optional) You may want to add some kind of flap to cover the belt holes in the box. 

Please do share pictures of your Boxer setup if you build one of these! Everybody's is a little different, and I love seeing them!