Safe chemistry LiMN means reduced risk of venting with flame or explosion. Due to the safety inherent in IMR safe chemistry batteries there is no protection circuitry added or built in. This provides a slightly shorter battery length to enable a good fit in most mods.
To ensure longevity, it is not recommended to allow the battery to discharge below 2.5V.
Please note that due to their inherent safety, IMR cells don't have a protection circuit built in. They should never be discharged below 2.5 volts or cycle life/performance will be reduced. Maximum charge voltage is 4.25 volts.