The iStick Pico S accepts both 21700 and 18650 batteries. Product includes high drain Avatar AVB 21700 battery (4000mAh) 

Parameter:
Size: 52.5mm*28.5mm*128mm (6.5ml version)
52.5mm*28.5mm*120mm (2ml EU version)
Weight: 198.7g (6.5ml version, without cell) 
192.9g (2ml EU version, without cell)
E-liquid capacity: 6.5ml / 2ml
Battery type: 21700 / 18650
Output wattage: 100W max
Output voltage: 0.5V-9V
Resistance range: 0.05Ω-3.0Ω (VW/Bypass mode)

7-Color LEDs
0.05Ω-1.5Ω (TC-Ni/Ti/SS/M1/M2/M3 mode)
Colors: red, black, white, silver, dazzling, blue

Standard configuration:
1×iStick Pico S
1×ELLO VATE (6.5ml / 2ml)
1×HW-N 0.2ohm Head
1×Avatar AVB 21700 
1×HW-M 0.15ohm Head
1×QC USB Cable
2×User Manuals
Spare Parts