Redragon PENUMBRA K687 vs CASTOR K631 Pro SEAluminum vs Wireless
Choose the Penumbra K687 for a premium, stationary typing experience, or the Castor K631 Pro SE for wireless flexibility and portability.
Which one should you get?
Get the
Redragon PENUMBRA K687
Aluminum
- CNC aluminum case for a solid, premium feel.
- Gasket mount design with five-layer noise dampening (PO foam, IXPE, PET, socket foam, silicone pad).
- Includes a dedicated control knob for media and lighting.
- Wired-only connectivity limits placement and device switching.
- Very heavy at 1500g (1.5kg), not portable.
- Only available with linear switches from the factory.
Get the
Redragon CASTOR K631 Pro SE
Wireless
- Tri-mode connectivity (wired, Bluetooth, 2.4GHz) for versatile use.
- Very lightweight at 470g and compact 65% layout.
- Includes a 2-in-1 USB-C to USB-C/A cable for broad compatibility.
- Plastic case construction feels less premium than aluminum.
- Bottom mount design may offer a firmer typing feel than gasket mount.
- Uses ABS keycaps, which can develop shine over time.
Your primary need dictates the choice. If you want a sturdy, acoustically tuned keyboard for a single desktop setup, the Penumbra K687's aluminum build and gasket mount deliver superior typing quality. If you need to move the keyboard between devices or locations, the Castor K631 Pro SE's wireless features and light weight are indispensable. Consider the Penumbra for a permanent upgrade and the Castor for flexible utility.
The differences that matter
Skip the 40-row spec sheet. These are the specs that change how each board feels, sounds, and fits your desk.
Redragon PENUMBRA K687
Redragon CASTOR K631 Pro SE
Layout size
75%
65%
Connection
Wired
Bluetooth, 2.4 GHz, Wired
Case material
Aluminum
Plastic
Switch options
Linear
Clicky, Linear
Mount style
Gasket Mount
Bottom Mount
- Redragon PENUMBRA K687
- Redragon CASTOR K631 Pro SE
- Performance
- 7971
- Build quality
- 7351
- Productivity
- 7149
- Customizability
- 6156
- Portability
- 6083
- Hot-swappable
What will you mostly use it for?
The Penumbra K687 is the clear choice for stationary, immersive use cases like gaming and programming, thanks to its premium build and functional layout. The Castor K631 Pro SE dominates in mobile scenarios like travel and offers more flexibility for office use with its wireless modes. For modding, the Penumbra's construction provides a better starting point, while content creators will value different features from each board.
Pick the Redragon PENUMBRA K687
- Wired-only connection on the Penumbra K687 eliminates potential wireless latency.
- The Penumbra's dedicated control knob provides quick access to media and volume.
- Its 75% layout retains function keys without requiring key combos.
Redragon PENUMBRA K687 vs CASTOR K631 Pro SE specs
Every tracked spec, side by side. Rows marked with a dot differ between the boards.
10 of 19 specs differ
Redragon PENUMBRA K687
Redragon CASTOR K631 Pro SE
Switch options
Hot-swappable
Mount style
Sound dampening
Layout size
Layout standard
Ergonomics
Knob
Display
Connection
Battery
USB-C
Case material
Keycaps
Weight
Dimensions
Backlight
N-key rollover
Released
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Redragon PENUMBRA K687 vs CASTOR K631 Pro SE: your questions
The Redragon Penumbra K687 features a CNC aluminum case. The Castor K631 Pro SE has a plastic case.
Yes. The Castor K631 Pro SE offers tri-mode connectivity, including USB-C wired, Bluetooth, and 2.4GHz wireless. The Penumbra K687 is wired-only.
The Penumbra K687 weighs 1500 grams (1.5kg), while the Castor K631 Pro SE weighs 470 grams. The Castor is significantly lighter and more portable.
Yes, both the Penumbra K687 and the Castor K631 Pro SE feature hot-swappable sockets. Redragon states the Castor's socket is compatible with 99.8% of 3-pin and 5-pin switches.
The Penumbra K687 is designed for a dampened sound, featuring five layers of noise dampening foam including PO foam, IXPE, and a PET sound pad. The Castor's acoustic profile is not described with the same level of dampening.
The Penumbra K687 uses a 75% layout with 81 keys. It retains the function row and navigation cluster while removing the numpad. The Castor K631 Pro SE is a 65% layout with 68 keys.
Yes, the Penumbra K687 includes a dedicated control knob. According to Redragon, it controls backlight brightness, volume, and media playback.
The Castor K631 Pro SE uses ABS keycaps. The keycap material for the Penumbra K687 is not specified in the provided information.
The Penumbra K687 comes with hot-swappable Dragon Chant linear switches. The Castor K631 Pro SE comes with quiet custom linear switches, and the metadata indicates it also offers clicky switch types.
The Castor K631 Pro SE includes a keycap puller, switch puller, and a 2-in-1 USB cable. The Penumbra K687 includes four spare switches and a detachable USB-C cable.
Yes. Redragon states that both the Penumbra K687 and Castor K631 Pro SE support software for customizing RGB lighting effects and creating macros.
The Penumbra K687 uses a gasket mount design. The Castor K631 Pro SE uses a bottom mount design.
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