Almost exactly the same as the remix source, with the exception that the frame has been 'extended' to fit a Creality 1Kg cardboard reel, so the reel just clears the frame at the top but allows more room at the bottom of the box to make space for more silica gel beads, and the bearing holders on the frame have a small lip to stop the bearings dropping out when removing from the box... and the spindle is a single piece that also is designed to snugly fit a Creality reel.
The original design had a split, chamfered spindle which did not let the reel run smoothly on the bearings and particularly the Creailty reels would hang too low and flop around.
I tried a number of ideas for 'universal' self-centred spindles, but all had some drawback - better just to resize this spindle diameter (leaving the bearing pegs alone) and print this one for a particular reel and use that.
I also had an idea to make the spindle hollow and with a 'cage' in the centre to hold silica gel but that got too complicated for not much gain, also might have contaminated the filament with tiny pieces of silica gel.
The other parts (filament guides) by BootUnstoppable are duplicated here for the collection, also included here is a hygrometer cage (I'm sorry I can't find who posted the original) that can be clipped onto a pneumatic connector nut inside the box that I thought was neat - not used it yet.

Items purchased to include in this construction:
Dry Boxes
https://www.amazon.co.uk/dp/B083J3LSXC

Silica Gel
https://www.ebay.co.uk/itm/364698058603

Roller bearings
https://www.ebay.co.uk/itm/296994838653

Pneumatic Tube Connectors
https://www.ebay.co.uk/itm/389191756199

Bowden in-line Tube Connectors (for the printer feed-tube)
https://www.ebay.co.uk/itm/256261916241

Digital Hygrometers
https://www.amazon.co.uk/dp/B0D3T89S8F

Stainless Steel button head bolts and nuts
https://www.amazon.co.uk/Stainless-Socket-Assorted-Assortment-Wrenches/dp/B09ZTP9WDL

Creality

K1

No

Yes

0.2

15-20%

Place the frame onto the inside of the box lid (it will only fit in one position) mark through the bolt holes and drill 4mm holes in the dry-box lid to accommodate the frame. Use M4 short nut and bolt ensuring that they do not foul the filament or reel.
Bore a hole for the Filament Guide (on the side, Top or bottom your choice see image) but must clear the silica gel on the bottom of the box. I put mine on the bottom because the K1 feeds upwards.
Fit a pneumatic pipe connector into the outside of the filament guide and fit the filament guide into the box with the retaining ring.
Bore a second hole in the box side, sized for the second pneumatic pipe connector, perhaps position it so the Hygrometer clip can fit onto the inside nut such that it does not foul the reel or the lid.
Fit the pneumatic storage connector into the box and fit the Hygrometer clip onto the storage pipe connector, with the Hygrometer.
Fit a pneumatic feed pipe to the pipe connector on the outside of the filament guide.
The second connector is to store the other end of the feed pipe sealed with some filament protruding into the box to make it easier to draw it out again when connecting back to the printer. While the feed-pipe is connected to the printer, the second connector is covered by a flexible plastic cap to maintain a humidity closed system.
Put a good layer of dried loose silica gel beads into the bottom of the box.
Press the bearings onto the spindle pegs, press the spindle into the centre of the cardboard reel.
hook the bearings, spindle and reel onto the frame, feed some filament through the filament guide and out of the feed pipe and then fit the lid assembly with the fame and the reel onto the box.
When storing the filament, leave about 5cm protruding from the feed pipe into the dry box.