Cheap vs Expensive SPG's internal differences

[Jiminy]

Hello I have recently been looking at SPG's and noticing the different prices. I know that plastic is cheaper than brass and glass and glow in the dark costs a little extra. That being said what are the internal differences?

One spg i am looking at lists this as a feature

COPPER BERYLLIUM BOURDON TUBE MECHANISM THAT NEVER GOES OUT OF CALIBRATION EVEN WITH HARD KNOCKS

 

[johndiver999]

A mechanical device that never goes out of calibration and has no means to manually adjust calibration. Those devices are spensive, somewhere up there with one of them there, perpetual motion machines.

 

[Yellowdog]

That would be the - Mares XR Pressure Gauge
Mares introduces its Extended Range (XR) Gear Line. The XR Pressure Gauge (PG) with graduation range of 0-5000 psi (0-360 bar), is a member of this new product line. This Italian made single reading gauge has a tempered glass lens, luminescent glow in the dark" screen and a brass housing with a double chrome, mirror-plated case treatment: assures the best look and maximum protection against corrosion. Copper beryllium bourdon tube mechanism that never goes out of calibration even with hard knocks for the greatest degree of accuracy and reliability.

I could be mistaken but I think most of the naked SPGs are made with a "Copper beryllium bourdon tube mechanism" From Dive Gear Express ( for 40% less ): "The SPG has an all brass chrome plated housing with a tempered mineral glass face and features a beryllium copper coiled Bourdon tube mechanism with a rack and pinion movement."

 

[Jiminy]

A mechanical device that never goes out of calibration and has no means to manually adjust calibration. Those devices are spensive, somewhere up there with one of them there, perpetual motion machines.

what mechanism do the cheaper devices use?

 

[Jiminy]

 

[tbone1004]

what mechanism do the cheaper devices use?

not being sold by brand name manufacturers. The good ones are all made by a company in Italy called Termo *not Thermo like the valve company*. The rest of the cheap ones are basically identical but made by one or two places in Asia.

The branding is what makes them cost that much more though

 

[Jiminy]

That would be the - Mares XR Pressure Gauge
Mares introduces its Extended Range (XR) Gear Line. The XR Pressure Gauge (PG) with graduation range of 0-5000 psi (0-360 bar), is a member of this new product line. This Italian made single reading gauge has a tempered glass lens, luminescent glow in the dark" screen and a brass housing with a double chrome, mirror-plated case treatment: assures the best look and maximum protection against corrosion. Copper beryllium bourdon tube mechanism that never goes out of calibration even with hard knocks for the greatest degree of accuracy and reliability.

I could be mistaken but I think most of the naked SPGs are made with a "Copper beryllium bourdon tube mechanism" From Dive Gear Express ( for 40% less ): "The SPG has an all brass chrome plated housing with a tempered mineral glass face and features a beryllium copper coiled Bourdon tube mechanism with a rack and pinion movement."

I did look at DGX gauges i and i do like them. The one thing i like more about ihe mares is the color coding on the face. It makes it easier to see halves and thirds but that's the only advantage i really see

 

[johndiver999]

Is that red at the end? I'm a little color blind.. If so, what color does red become at depth? A Black pointer with a black background at the most critical portion of the scale? This always seemed ridiculous to me.

 

[rhwestfall]

my current favorite:

 

[CT Sean]

That Mares sure looks the same as all the other Termo-made brass and glass SPGs. I find it HIGHLY unlikely that they are any different internally. The DGX version is only 60.00. A pretty colorful face might looks nice on the surface, but simple black and white works better underwater, in my opinion and experience anyway. I was wow'ed by a pretty SPG once upon a time (ooo it has BAR ans PSI on it and a handy green/yellow/red sections!) I replaced it with a simple black and white shortly after

If nothing else, I couldn't justify spending 50.00 extra to get some extra blue and red ink and a Mares logo on the dial.