Difference between Cammenga Phosphorus and Model 27?

[avigo]

Just bought a used Cammenga Phosphorus compassions for $15. Honestly didn't look closely at the photos and assumed it was the Model 27. However, it does not say Model 27. Photo attached of what it looks like.

What are the differences between these two compasses? 

 

[avigo]

[Survival]

Even though its marked US it looks commercial to me.  No FSN or other markings.  The military issue ones I'm familiar use a radioactive isotope as an illumination source and are well marked.  Probably plenty of others will post who know more then I do.

[avigo]

29 minutes ago, Survival said:

Even though its marked US it looks commercial to me.  No FSN or other markings.  The military issue ones I'm familiar use a radioactive isotope as an illumination source and are well marked.  Probably plenty of others will post who know more then I do.

 

 

Thanks. It also says "phosphorus" instead of "phosphorescent" which is strange.

Can't find any examples that they make a specific military and commercial version

[Doctorofwar]

Looks like commercial markings.  Prior to tritium these type of military compasses were phosphorescent, someone more knowledgeable than me could tell you the year they switched but it I think it was more than 40years ago.  Cammenga did make both phosphorescent and tritium compasses for the commercial market more recently, you had to pay a premium for the tritium version.