For years now, Mionix mice have been my primary go-to for both gaming and work. Partly for their specs, sure, but mostly for the things most important to me as someone who spends 10-12 hours a day using a mouse: build quality and ergonomics.

I need a mouse that feels good and lasts for years, and with each successive refresh to their flagship Naos line, Mionix delivered that. This year, the company is trying something different, with the Castor, due out in September. And I’m not really a fan.

Look, on paper, it’s a good mouse! Great specs (up to 10,000DPI, 32bit ARM processor, 5 macro profiles), and those same old Mionix quality components, including a nice thick corded cable and their trademark matte finish.

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Where the Castor went wrong for me, though, was in the concept itself. Here are two lines in particular from its press release that I want to talk about:

The CASTOR’s unique shape has been developed to be used by right-handed players to equally support palm, claw and fingertip-grip.

So it’s trying to be a Jack of all Trades. Ambitious; the best mice tend to cater towards one of those and run with it, so best to accommodate it. Yet the claim that it’s good for palm usage, which I prefer, seems especially off when you consider this:

The mouse has a dedicated pinky-and ring-finger support-groove which makes it extremely comfortable to hold and lift.

Wrong. This mouse is too small for that. I have pretty average sized-hands, and my ring finger could barely sit on it, let alone my pinky, which was just left kinda...dangling out the side. Below is a size comparison so you can see what I’m talking about: the Castor is on the right, the Naos 7000 on the left.

The smaller size gets you in other places, too. The reduced surface area over the palms was a downer in both “palm” and “claw” grip styles, while the bland ergonomics affected comfort regardless of which grip I was using.

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Combine all this and I found that over extended use—and it didn’t matter which grip I tried—it became uncomfortable after just a couple of hours.

This might sound like nit-picking, not to mention an unfair comparison since the Naos 7000 is a big flagship mouse, but the Castor isn’t a budget peripheral! Had this been aimed at a lower end of the market, something kids or cash-strapped gamers could aim for, it would be great! But I’ve continually compared the Castor to the Naos 7000 for a reason: it’s exactly the same price as the older device ($70), and while the Castor boasts slightly better specs (same processor, but 10,000DPI vs the 7000’s 7000DPI), the Naos 7000 is a much more comfortable mouse for long-term use.

The design decisions made here are a shame, because I love the feel of the Castor action. It’s a precise, snappy mouse, and the scroll wheel and buttons have a great, hefty click to them. There’s also a patch of rubber near the thumb that, while a bit of a dust magnet, has a nice soft touch to it.

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Tiny humans or gamers who like to constantly switch between grip styles might still want to check it out. Since that excludes most of you, though, you might want to pass. Or get the Naos 7000 instead.

If you’re interested in the full list of specs, here you go, from the Castor’s product page:

TECH SPECS

  • 32bit ARM Processor running at 32Mhz
  • 6 fully programmable buttons
  • 3 steps in-game DPI adjustment
  • 2 integrated LEDs in 2 colour zones
  • Up to 16.8 Million LED colour options
  • Color shift, Solid, Blinking, Pulsating and Breathing effects
  • On-Board memory 128 kb built-in memory
  • Gold Plated, Full speed USB 2.0 connection with Plug and Play
  • Cable 2m long PVC cable with cable reinforcer

SENSOR SPECS

  • PMW – 3310 gaming grade IR-LED optical sensor
  • Up to 10000DPI
  • MAX tracking speed of at least 5.45m/sec (215 IPS)
  • No positive or negative hardware acceleration
  • Adjustable Lift Off Distance

Dimensions & Weight

  • 122.46×70.42×40.16 mm / 4.82×2.77×1.58 in
  • Weight (w/o cable): 93.8 gr
  • Weight (cable incl.): 141.5 gr