If you are looking for an external 18650 battery for your vape device (SMOK RPM 160, Geekvape Aegis Boost Plus, SMOK RPM 2, VOOPOO Drag X) than MXJO is a reputable brand at a competitive price. 

The specifications for this battery:

• Size: 18650
• Style: flat top
• Nominal Capacity: 3500mAh
• Discharge Current: 10A maximum continuous, rated 20A
• Nominal Voltage: 3.7v
• Maximum Voltage: 4.2v
• Approximate Dimensions: 18.22mm x 64.89mm
• Approximate Weight: 44.8g