These 16340 batteries are short for protected batteries, i.e. they are very close to 34 mm long (Same size as CR123 batteries). This battery can only replace a CR123 battery in equipment designed for LiIon, because it has higher voltage than a CR123 battery.

Specifications:

• 750mAh IC PROTECTED Rechargeable Cell (4.2V hot off charger)
• Measures only 34.4mm in height (+/-0.1mm) and 16.7mm in width
• IC protected for a) over-charge, b) over-discharge, c) short circuit, d) current overflow of 3A+
• True protrude top design, fits all flashlights
• High discharge rate 3A+
• Nominal voltage: 3.7V, charge up to 4.2V, use CC/CV charger to charge
• Reinforced steel plate bottom, highly efficient protective PCB design
• Packaged in individual box and anti-static bag