Nitecore Li-Ion Battery Type 16340 - NL166 - 650mAh 3.7V RCR123A
A powerful power cell developed by DLG from safe chemical composition (Lithium-Manganese)The manganese does not react with lithium, therefore these cells have a high intrinsic safety.

Note: Lithium cells may only be operated with protection electronics!

Safety note:
Please note that lithium cells may only be used by competent persons.
Incorrect handling or short-circuiting can lead to fire or explosion.

Further characteristics:
Lithium-ion batteries are thermally stable and are not subject to memory effect.
They work on the basis of lithium and are characterised by a high energy density.

Notes: 

A special charger is required for charging lithium-ion batteries, which charges the batteries according to a special charging procedure. (CCCV = constand current, constant voltage.) The batteries must not be charged above a voltage of 4.2 volts, otherwise there is a risk of fire and explosion. It is advantageous to charge the batteries only up to approx. 4.1 volts, as this significantly increases the service life or the number of charging cycles (possibly up to double). Only lithium ion chargers may be used for charging. However, the cheap chargers sometimes have the disadvantage that they do not switch off safely at the end of the charging process, but continue to charge the batteries with a small charging current, which can be dangerous.

Furthermore, rechargeable batteries and batteries do not belong in household waste! Please dispose of them as prescribed by law in the municipal collection points or in the [usually green] containers provided by retailers;