The flange rests on the base ring, the center post passes through the core hole to limit sideways movement, and the whole desiccant bag sits in the central breathable compartment. The main lid is fixed with short screws, and the central boss stops the core lid jumping out; the lid does not press the flange or winding. The small lid does not need turning; bags are changed and trays taken from above; no airtightness, moisture absorption efficiency or brand universality is claimed.

Listed part dimensions are outer bounds; usable interior space is given in this model's specifications.

The ZIP contains the complete STL and STEP files, a size list and notes. Version 1.0.0 Use the complete set of files of the same version and size for matching parts. Preview colors are for reference only; STL files carry no color.

Ranges are set by this model's structure; each combination must pass the studio's structure checks; matching parts update with the parameters.

1. Measured spool diameter ≤ 210, width ≤ 70, narrowest core hole ≥ 52 mm. Must have a flat bottom flange, supported by the base ring; cable must not stick out beyond the flanges. 0.5 mm design clearance on each side of the central post; universal brand fit is not promised.
2. Put only desiccant in complete sealed fabric bags; recommended maximum envelope Ø43.0 × 70.0 mm; do not pour in loose granules or powders. The core compartment and four top holes vent air; it only separates the bag from the filament and gives no moisture absorption efficiency or airtightness guarantee.
3. Full BOM: 1 printed outer case, 1 main lid, 1 core lid; supply 4 M3×12 fully threaded screws (shaft Ø3, head Ø ≤ 5.5, height ≤ 3 mm), 4 M3 nuts (AF ≤ 5.5, height ≤ 2.4 mm) and 1 complete desiccant bag. Keep this 12 mm standard length when the lid/ear thickness changes; do not scale hardware with the whole package.
4. Installation: put the nuts in from under the four ears, place the spool and the complete bag, lift the core lid straight on, lower the main lid's locating skirt to the rim and screw the four screws in from above. The screw head adds 3 mm, with the tail slightly below the ear bottom and outside the compartment; the lower nut holes and upper tool holes always stay outside the spool. Hardware is not included in the printed parts.
5. Remove 4 screws, then lift the main lid off; lift the core lid to change the bag, and lift the spool straight up around the center post. The core lid does not need turning, and its outer diameter is smaller than the core hole; a 0.4 mm gap between the main lid boss and the core lid stops the small lid jumping out without pressing on the flange or cable.
6. For slicing, put the outer case base down and both lids top down; check the loads on the center seam, round wall and ears. Before use, test-print to check the 0.4/0.5 mm fits, strength, drops, moisture absorption and transport retention; no gasket; not claimed to be airtight or waterproof.

Import into your slicer in millimeters and check build volume, orientation and supports for each part. Test-print lids, drawers and connectors first, and print the full set once the fit is confirmed.