GE 70w ConstantColor CMH Precise Unique Arc Tube: Full Power
1 x 70w GE single ended ceramic discharge metal halide lamp with G12 cap in colour 930 at full power.

This lamp features quite a unique looking arc tube. I've not seen anybody else make ones like this!
It appears to have a hybrid design of arc tube with one half featuring the traditional squared end of the early CDM lamps and the other half having the formed arc tube profile of the modern lamps.
Forming the latest ellipsoidal shaped arc tubes is extremely expensive, the most being the single piece arc tubes and to a lesser extent the two-piece designs.
GE’s design here is cheaper and slightly better way of doing it. It is still a two piece ceramic but the interface is shifted off-centre to one side. This makes assembly very much easier and cheaper, and being asymmetric has the advantage that when used base up the thermal profile is actually better than an ellipsoidal arc tube, and performance can be slightly improved.

GE 70w ConstantColor CMH Precise Unique Arc Tube: Full Power

1 x 70w GE single ended ceramic discharge metal halide lamp with G12 cap in colour 930 at full power.

This lamp features quite a unique looking arc tube. I've not seen anybody else make ones like this!
It appears to have a hybrid design of arc tube with one half featuring the traditional squared end of the early CDM lamps and the other half having the formed arc tube profile of the modern lamps.
Forming the latest ellipsoidal shaped arc tubes is extremely expensive, the most being the single piece arc tubes and to a lesser extent the two-piece designs.
GE’s design here is cheaper and slightly better way of doing it. It is still a two piece ceramic but the interface is shifted off-centre to one side. This makes assembly very much easier and cheaper, and being asymmetric has the advantage that when used base up the thermal profile is actually better than an ellipsoidal arc tube, and performance can be slightly improved.

387A7153.JPG 387A7188.JPG 387A7218.JPG 387A7227.JPG 387A8187.JPG
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Filename:387A7218.JPG
Album name:FrontSideBus / HID: Metal Halide
Filesize:1224 KiB
Date added:05 Jun, 2026
Dimensions:1365 x 2048 pixels
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Beta 5   [05 Jun, 2026 at 11:02 PM]
These are really cool, shows how optimised they were getting metal halide towards the end with the cheapest production and best performance. Did they make these in colour 942 too? Got to look out for one of these as I only have the normal ones so far!
FrontSideBus   [06 Jun, 2026 at 09:37 AM]
I've only ever seen these arc tubes in their Precise red box range and only in 3000k.
dor123   [07 Jun, 2026 at 07:42 PM]
I'm wondering if this is a prototype?
Beta 5   [07 Jun, 2026 at 09:30 PM]
@FrontSideBus, ok so a fairly limited range, still another one worth adding to to the collection Cool
@dor123, these were definitely a mainstream product, I have seen them about and they had normal packaging so weren't just an experiment.

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