A proper 18650-battery (18.6 x 70 mm / 0.73" x 2.76") you can recharge using a microUSB-charger.

Features

• Charging options: Micro-USB-port or Charger
• Unique structural design for better impact-resistant
• Built-in over charge, over discharge, short circuit and three sets of over-heat protection ensure the safety and good performance of the battery
• Designed to retain up to 75% of its original capacity at 500 full charge and discharge cycles
• Warranty: 12 months
• Recommended charger: Fenix ARE-C1, ARE-C1+, ARE-C2, ARE-C2+, ARE-X1, ARE-X1+, ARE-X2
• Micro-USB charging cable not incluced