Compare Redragon PENUMBRA K687 vs CASTOR K631 Pro SE Differences Side by Side

This comparison is for buyers deciding between Redragon's premium wired offering and their versatile wireless model. The Penumbra K687 offers a CNC aluminum case, gasket mount, and extensive sound dampening for a high-quality feel. The Castor K631 Pro SE counters with tri-mode wireless connectivity and a much lighter, more portable 65% form factor. The decision hinges on prioritizing material quality and acoustics versus connectivity freedom and ease of transport.

Model
	70		Select a keyboard to compare
Rating	0.0 stars (0 reviews)	0.0 stars (0 reviews)
Purchase Options
Main differences	Released in 2025 Has Linear switch options Available in a 75% layout Comes with a knob Has built-in sound dampening Uses a Gasket Mount mounting style Supports Wired, Wired only connectivity Weighs about 1500 g Sized at 43 x 133 x 43 mm Made with a Aluminum case	Released in 2023 Has Clicky, Linear switch options Available in a 65% layout Uses a Bottom Mount mounting style Supports Bluetooth, 2.4 GHz, Wired, Wireless connectivity Equipped with a 1600 mAh battery Weighs about 470 g Sized at 40 x 309 x 104 mm Made with a Plastic case Features ABS keycaps
Score	Scores Performance: 79.6 Build Quality: 72.9 Productivity: 71.3 Customizability: 62 Portability: 60.2	Scores Performance: 70.8 Build Quality: 50.9 Productivity: 49.4 Customizability: 56.4 Portability: 83.4
Name	Name Redragon PENUMBRA K687	Name Redragon CASTOR K631 Pro SE
Release year	Release year 2025	Release year 2023
Switch Options	Switch Options Linear	Switch Options Clicky, Linear
Profile	Profile Normal Profile	Profile Normal Profile
Hot Swappable	Hot Swappable	Hot Swappable
Layout Size	Layout Size 75%	Layout Size 65%
Layout Standard	Layout Standard ANSI	Layout Standard ANSI
Layout Ergonomics	Layout Ergonomics Normal	Layout Ergonomics Normal
Knob Support	Knob Support	Knob Support
Display Support	Display Support	Display Support
Mac/Win Support	Mac/Win Support	Mac/Win Support
Multi-Media Keys	Multi-Media Keys	Multi-Media Keys
USB-C	USB-C	USB-C
USB passthrough	USB passthrough	USB passthrough
Connection	Connection Wired, Wired only	Connection Bluetooth, 2.4 GHz, Wired, Wireless
Polling Rate	Polling Rate -	Polling Rate -
Battery capacity	Battery capacity -	Battery capacity 1600 mAh
Hall Effect Support	Hall Effect Support	Hall Effect Support
QMK Support	QMK Support	QMK Support
VIA Support	VIA Support	VIA Support
VIAL Support	VIAL Support	VIAL Support
N-Key Rollover	N-Key Rollover	N-Key Rollover
Rapid Trigger	Rapid Trigger	Rapid Trigger
Mount Style	Mount Style Gasket Mount	Mount Style Bottom Mount
Screw in Stabilizers	Screw in Stabilizers	Screw in Stabilizers
Sound Dampening	Sound Dampening	Sound Dampening
Backlight	Backlight Rgb	Backlight Rgb
Case Colors	Case Colors	Case Colors
Case Material	Case Material Aluminum	Case Material Plastic
Keycaps Material	Keycaps Material -	Keycaps Material ABS
Dimensions	Dimensions 43 x 133 x 43 mm	Dimensions 40 x 309 x 104 mm
Weight	Weight 1500g	Weight 470g

*Something incorrect or missing? Please

let me know

!

Pros and Trade-offs

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.

Redragon PENUMBRA K687

+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.
+75% layout provides dedicated function keys without a full-size footprint.
+Comes with four spare switches and a detachable USB-C cable.

−Wired-only connectivity limits placement and device switching.
−Very heavy at 1500g (1.5kg), not portable.
−Only available with linear switches from the factory.

Redragon CASTOR K631 Pro SE

+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.
+Hot-swappable PCB supports both 3-pin and 5-pin switches.
+Comes with both a keycap and switch puller in the box.

−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.
−Lacks a dedicated control knob or extensive sound-dampening foams.

Which Keyboard Is Better for Your Needs?

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.

GamingRedragon 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.

OfficeRedragon CASTOR K631 Pro SE

•The Castor K631 Pro SE offers Bluetooth and 2.4GHz wireless for connecting to multiple devices.
•It is significantly lighter at 470g, making it easier to reposition on a desk.
•Its quiet custom linear switches, as described by Redragon, may be less disruptive.

ProgrammingRedragon PENUMBRA K687

•The Penumbra K687's 75% layout includes dedicated function keys (F1-F12) for IDE shortcuts.
•Its aluminum case and gasket mount with five-layer dampening aim for a more comfortable, sustained typing feel.
•The inclusion of a knob can be mapped to scroll or adjust settings in code editors.

TravelRedragon CASTOR K631 Pro SE

•The Castor K631 Pro SE weighs 470g versus the Penumbra's 1500g.
•Its 65% layout is more compact than the 75% layout.
•Wireless operation removes the need to manage a cable on the go.

ModdingRedragon PENUMBRA K687

•The Penumbra K687 features a gasket mount design, which is often preferred for a softer typing feel.
•It includes five specific dampening layers (PO foam, IXPE switch foam, PET sound pad, bottom socket foam, silicone bottom pad) for acoustic tuning.
•Both keyboards are hot-swappable, but the Penumbra's build offers a more mod-friendly foundation.

Content CreationTie

•The Penumbra's dedicated knob is excellent for timeline scrubbing or brush size adjustment.
•The Castor's wireless connectivity allows for a cleaner desk setup for filming or photography.
•Both keyboards support per-key RGB customization via software for aesthetic setups.