Rat, Panasonic CR123A cells are one of the best cells available. Premium quality CR123A cells are made in both the U.S. and Japan (Sanyo's are also made in Japan and are considered top notch, as well). The one and only plant in the U.S.A. (which is owned by Panasonic) that manufactures CR123A cells, also makes Duracell, Battery Station, as well as all other "made in U.S.A." CR123A cells, to the customers specification. All of these cells are considered "premium" cells, however their exact characteristics may be slightly different due to the customer's specific requests.
One problem that appears unfortunately, are "counterfeit" Panasonic cells that have shown up in some places, such as ebay. Generally, if the price of quality CR123A cells seems "too good to be true", they are most likely counterfeit cells, and should be avoided. So depending on where your friend purchased the cells he has, they may be genuine cells, or they may not.
These are Primary lithium cells, they don't need protection. Only rechargeable cells/batteries might have a protection circuit.
All lithium primary cells and lithium ion cells should have a PTC. A "PTC" is a "Positive Thermal Coefficient" device, and is a requirement needed to meet shipping safety regulations before lithium, or lithium ion cells can be shipped. Many of the inexpensive Chinese CR123A, and Li-Ion cells do not have the required PTC installed, however. This includes nearly all of the counterfeit cells I mentioned above. These cells are potentially dangerous.
It is also important to note that a "PTC' is an entirely different device than a "PCB' (printed circuit board), or "protection circuit" which has been added to Li-Ion cells by third parties (manufacturers of Li-Ion cells do not manufacture individual Li-Ion cells with PCB protection circuits), which adds protection from under and over voltage of Li-Ion cells when either being charged, or in use.
PTC's are provided to limit, or cutoff the circuit within the cell when a predetermined maximum temperature and/or current threshold has been breached, such as a direct short. This applies to both lithium primary and Li-Ion cells. Also, PTC's are installed at the positive end of the cell under the nipple, by the cell manufacturer, and PCB's at the negative end of the cell, again by third parties.
Dave
