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Polymaker PolyBox Edition II 3D Printer Filament Dry Box – Humidity Below 15% | 1.75 & 2.85 mm

The Polymaker PolyBox Edition II is a sealed filament dry box that holds two 1 kg spools or one 3 kg spool and keeps 3D printing filament below 15% relative humidity — during storage and while you print.

  • ✓ Holds 2×1 kg or 1×3 kg spools · 1.75 & 2.85 mm filament
  • ✓ Built-in hygrometer + reusable silica-gel desiccant · humidity below 15%
  • ✓ Feeds filament straight into the printer while sealed

$70

Prices follow supplier cost and stock availability and are updated regularly. The price you see is today's price — once you order, it's held for 7 days.
Keep every spool print-ready

Keep every spool print-ready

Humidity held below 15%

A built-in high-precision hygrometer and reusable silica-gel desiccant hold the internal humidity below 15% — the range that stops Nylon, PVA, and PolySmooth from absorbing moisture and causing warping, poor layer adhesion, or brittle prints.

A materials engineer on the line

Not sure which materials need active drying, or how to store them between jobs? Our materials engineers have run these filaments and can advise on storage, drying, and handling. Sub-4h reply, NDA standard.

About this product

FEATURES

The Polymaker PolyBox Edition II is a sealed 3D printer filament dry box designed to provide the ideal storage environment for your 3D printing filaments. It is compatible with all 3D printers and helps protect your materials from moisture, ensuring consistent, reliable prints every time.

Key features include:

  • Holds two 1kg spools or one 3kg spool, making it versatile for different filament sizes
  • Optimum environment for filament storage, preventing moisture-related issues like warping or poor adhesion
  • Compatible with all 3D printers, making it a universal solution for filament care
  • Feeds filament directly to the printer while sealed, keeping it dry during the print

With the PolyBox Edition II, you can trust that your filament is stored properly and stays print-ready. Keep your materials dry and your prints consistent, no matter the filament type.

Polymaker PolyBox Edition II filament dry box with built-in hygrometer

PolyBox™ includes a built-in high-precision hygrometer and silica gel desiccant sachets to control and absorb moisture from the air. The humidity within the box is maintained below 15% to prevent the filament from absorbing moisture during storage and even during the 3D printing process. It is specifically designed for Nylon, PVA, PolySmooth™ and other highly hygroscopic 3D printing materials.
However, it is good practice to keep all 3D printing filaments inside the PolyBox™ to preserve the optimum printing quality.
PolyBox™ is compatible with both 1.75mm and 2.85mm filaments and can contain up to two 1kg spools or one 3kg spool.

To install the hygrometer battery
Slide down the hygrometer battery cover.
Remove the battery from the package, insert it in the designed compartment and put back the cover.
Check if the front display switches on. When you notice that the hygrometer display is fading, replace the button battery 1.5V LR44.
Note: The provided battery will last approximately 3 months.

To install the rods
Slide two bearings onto both ends of the steel rod, then snap the rod and bearings into the PolyBox™.

To install the desiccant sachets
Remove the set of desiccants from the package and check if the sealed bag is intact.
If there are any leaks, please dry the sachets before using them. The provided desiccant bags can be dried in a microwave for 4 times 5min (defrost mode); make sure to flip the bags upside down between each iteration. Use oven mitts to touch the desiccant bags.
Note: other types of desiccant may not have the ability to recover and be reused.
Do not expose the desiccant sachets to the air for too long. We highly recommend silica gel for the type of desiccant.
Put the two desiccant bags into the PolyBox™, one in each compartment.
Close the two compartments with the two grids.

To install the filament guide
Cut the filament guide according to your need (distance from the PolyBox™ to the 3D printer) and insert it in the rubber holes on the back or on the top.

To place the spool

Place the spool in the PolyBox™ and feed the filament through the rubber plug.
Note: Make sure the material is fully dried before putting it in the PolyBox™.
Place the cover on the PolyBox™.
You should feel a small friction which ensures the fit. Make sure the cover fits correctly in the base to ensure an airtight environment for the spools. Do not open the PolyBox™ too frequently, and close all the unused rubber plugs to preserve the desiccant.
Gently pull the filament out to check if the spool rolls smoothly.
After 2 hours you should see the inside humidity dropping below 15%. The time will depend on the room humidity. The hygrometer should always display a humidity level below 15%.
Note: The minimum humidity level that can be displayed is 10%.
If the hygrometer displays a humidity level above 20%, replace the desiccant.

Brand Polymaker
Printing Materials Plastic Filaments

Common questions

Don't see yours? Email [email protected] — NDA standard, typical reply within 4 hours.

Which 3D printers is the PolyBox Edition II compatible with?
The PolyBox Edition II works with any 3D printer. It sits beside the machine and feeds filament through a sealed port, so it is not tied to a specific brand or model. It accepts both 1.75 mm and 2.85 mm filament and holds two 1 kg spools or one 3 kg spool, making it a universal dry-storage solution for FDM printers.
Which filaments benefit most from the PolyBox?
Hygroscopic materials benefit most — Nylon (PA), PVA, PolySmooth, TPU, PC, and PET-based filaments all absorb moisture from the air and print poorly once wet. Keeping them in the PolyBox below 15% humidity prevents warping, stringing, poor layer adhesion, and brittle parts. As good practice, Polymaker recommends storing all filament in the PolyBox to preserve print quality.
How does it keep filament dry while printing?
The PolyBox is a sealed enclosure with two reusable silica-gel desiccant sachets and a built-in hygrometer. Filament feeds out through a rubber port directly to the printer, so the spool stays sealed and dry during the entire print, not just in storage. The internal humidity typically drops below 15% within about two hours; if the hygrometer reads above 20%, it is time to dry or replace the desiccant.
What spool sizes and filament diameters does it hold?
The PolyBox Edition II holds two 1 kg spools or one 3 kg spool and works with both 1.75 mm and 2.85 mm filament. The internal rods and bearings let spools roll smoothly as the printer draws filament. The desiccant sachets can be recharged in a microwave or oven and reused, so ongoing running cost stays low.

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