The Vaporesso XROS Series pods come in packs of 4 and are available in 0.6ohm and 1.2ohm resistances. They are designed to be used with the XROS 3 kit. The 0.6ohm pod works best with 50/50 e-liquid and is designed for restricted direct lung vaping. Whereas, the 1.2ohm coil is suited towards mouth to lung vaping and works best with nic salt. The filling port is located under the mouthpiece and can be accessed by snapping off the black drip tip.