Chess clocks are one of the few chess items that surprisingly do not have many detailed comparison videos or guides online.

In this comparison, we are going to look at the physical characteristics and practical differences between two of the most popular digital chess clocks used by chess players and tournament competitors:

  • ZMF Pro Chess Clock

  • Chronos GX Chess Clock

Both clocks you see pretty often at chess tournaments, local clubs, blitz games, and also online chess streams or posts.  

They’re kind of premium chess clocks, and in most places they usually run about 100 to 110 USD, give or take.

Why These Two Chess Clocks Are So Popular

The main reason these clocks were picked for comparison is, pretty simple:

They are two of the most recognized digital chess clocks you see in competitive chess, basically everybody knows them.

You frequently see them:

  • At chess tournaments

  • In blitz events

  • At local chess clubs

  • In YouTube chess videos

  • During tournament practice sessions

The reviewer also mentioned personally using both clocks in blitz games and club matches.

First Impressions and Packaging

The packaging styles of both clocks are completely different.

Chronos GX Packaging

The Chronos box is very simple and straightforward.

It focuses more on minimalism without adding extra product details or branding information.

ZMF Pro Packaging

The ZMF Pro box includes:

  • Product disclaimers

  • Feature information

  • Additional product details

This gives the packaging a more premium and informative feel.

Inside the box, you also receive instruction manuals.

The instructions are important because even though these clocks are not extremely difficult to program, setting advanced time controls becomes much easier when you keep the manual available.

Programming and Time Control Support

Before comparing physical features, one important point was mentioned clearly:

Both clocks support nearly every major chess time control format.

Supported formats include:

  • Fischer Increment

  • Bronstein Delay

  • Standard Delay

  • Classical Tournament Controls

  • Multi-stage tournament timing

For example, both clocks can handle advanced FIDE-style controls such as:

40/120 + 20/60 + 15

That means:

  • 40 moves in 120 minutes

  • Next 20 moves in 60 minutes

  • Final 15 minutes added afterward

So from a programming perspective, both clocks are highly capable.

Display Size Comparison

The first major physical difference is the display size.

ZMF Pro Screen

The ZMF Pro has approximately:

  • 3.5-inch display

Chronos GX Screen

The Chronos GX has approximately:

  • 2.5-inch display

 

This means the ZMF Pro offers significantly more screen real estate and is easier to read during gameplay.

For many players, especially during fast blitz or tournament games, readability matters a lot.

Screen Contrast and Visibility

The reviewer personally preferred the contrast on the Chronos clock.

Why?

Because the figures are smaller and the blank space inside the digits is harder to spot, a bit less noticeable overall.

Still, this is mostly a personal preference rather than a big advantage, really.

Both clocks remain fully readable during play.

Physical Buttons vs Touch Controls

This is one of the biggest differences between the two clocks.

ZMF Pro Uses Physical Buttons

The reviewer strongly preferred physical buttons.

The ZMF Pro uses actual mechanical switches similar to mechanical keyboard switches.

These switches:

  • Feel tactile

  • Are highly durable

  • Can survive millions of presses

  • Provide clear feedback during gameplay

This makes the clock feel extremely reliable during blitz and bullet games.

Chronos GX Uses Touch Controls

The Chronos GX mainly uses touch-sensitive controls.

Interestingly, the reviewer mentioned that touching the clock creates a slight sensation or vibration feeling in the fingers, although it is unclear whether this comes from:

  • Actual vibration

  • Sound resonance

  • Psychological feedback

The reviewer also mentioned that the Chronos version discussed mainly comes in touch-control style.

Battery Compartment Design

Another important physical difference is battery access.

ZMF Pro Battery Access

To access the battery compartment on the ZMF Pro:

  • Multiple screws must be removed

  • The case needs to be opened

 

Chronos GX Battery Access

The Chronos clock places the battery compartment directly on the bottom with easier access.

Both designs are intentional because chess clocks must prevent accidental battery disconnects during tournament games.

This becomes extremely important during:

  • Blitz games

  • Time scrambles

  • Competitive tournament situations

As explained in the source, imagine winning a game with your opponent on one second, then suddenly the display dies after slamming the clock.

Reliable battery security is therefore critical.

Build Quality and Surface Finish

The clocks also feel different physically.

Chronos GX Finish

The Chronos clock has:

  • More glossy finish

  • Smoother touch feel

However:

  • It attracts fingerprints more easily

 

ZMF Pro Finish

The ZMF Pro uses:

  • Matte or powder-coated finish

Advantages include:

  • Better grip

  • Fewer fingerprints

  • Better handling during sweaty hands or long sessions

 

Delay Display Feature Comparison

One timing feature stood out strongly during the comparison.

Chronos Delay Display

The Chronos clock shows delay timing in a smaller corner section.

ZMF Pro Delay Visualization

The reviewer preferred how the ZMF Pro visually counts down delay time in a larger and more visible way.

This becomes extremely useful when:

  • You have low remaining time

  • You rely heavily on delay

  • You want visual confidence during time pressure

The reviewer mentioned that seeing the full delay countdown provides more ease and comfort during stressful positions.

Final Verdict: Which Chess Clock Is Better?

According to the reviewer, you really cannot go wrong with either chess clock.

Both are:

  • Very sturdy

  • Tournament-ready

  • Popular among serious players

  • Reliable for blitz and classical games

However, the biggest deciding factors for most buyers will likely be:

  • Screen size

  • Physical buttons vs touch controls

  • Battery compartment accessibility

Who Should Buy the ZMF Pro?

Choose the ZMF Pro if you prefer:

  • Physical mechanical buttons

  • Larger display

  • Matte grip finish

  • Easier delay visualization

  • Strong tactile feedback

Who Should Buy the Chronos GX?

Choose the Chronos GX if you prefer:

  • Compact design

  • Simpler appearance

  • Glossy premium feel

  • Touch-sensitive controls

  • Traditional tournament-style clock aesthetics

Conclusion

Both the ZMF Pro and Chronos GX are premium digital chess clocks designed for serious chess players.

The ZMF Pro focuses more on:

  • tactile interaction

  • visibility

  • modern physical controls

Meanwhile, the Chronos GX offers:

  • classic tournament reliability

  • compact design

  • minimalist functionality

At the end of the day, the best chess clock depends on your personal playing style and preferences.