Protec helmets.....now this subject will get collectors talking, fighting, and arguing. Some collectors will tell you that these were never used by USSF (which is ENTIRELY wrong). Some collectors will tell you that they aren't used now. Some collectors will tell you that they are worn into combat. Myself, I am a believer that they are still being used by USSF right now. I believe they are used mainly by SEAL's for boarding parties. Possibly by Delta for assaults. HOWEVER, I believe that you will see a decline in use of these helmets over the next few years.
The reason I say this is simple. The Protec helmets were used a lot by USSF in the 80's and 90's. The reason being is simple. When they were doing boarding parties, assaults, CQB, etc. they used the Protec as head protection from bumps, falls, and other head injuries. The PASGT helmet offered great ballistic protection, but offered very little bump/fall protection. The inside of the Protec helmets were made of a plastic/styrofoam type material that offered great bump protection, but absolutley NO ballistic protection. The SF guys were more worried about head injuries (which will incapacitate you on the battlefield) than being shot. Furthermore, the Protect helmets didn't ride as far down on the head like the PASGT, thus offering better hearing for the soldiers. Lastly, the PASGT helmets were extremely heavy. When you are a SF operator, speed is paramount.
I am sure there were other reasons why they wore the Protec helmets, but those are three good reasons why they did. For almost two decades, the only ballistic helmet availiable to the USSF was the PASGT. They had to trade off ballistic protection for bump protection. Not a very fair trade in my opinion.
Fast forward to the late 90's. When the military placed more emphasis on the capabilities of the USSF, there began to be more options for headgear for the SF guys. They began to manufacture helmets that were lighter, had cuts for communicatiion devices (headphones), had padding on the inside, and still offered the same or better ballistic protection as the PASGT. For once, the USSF had a helmet that offered ballistic protection and bump/fall protection!!! I am referring to the MICH/ACH/Gallet and other USSF helmets.
As the technology gets better and the helmets more advanced, I think you will see the Protec helmets go the way of the dinosaurs. I am sure there will be some who disagree with my analysis, but only time will tell on this subject.