From the manufacturer:
Reflex introduces a unique user refillable pod. Manufactured from Black Ultem (PEI), the pods are extremely heat-resistant and are completely Bisphenol A (BPA) free. Each pod is individually tested for leakage, wicking, and coil uniformity. Each pod will vape exactly the same as the last. The pods are specifically designed to allow the device’s advanced sensors to constantly measure changes in air flow and coil resistance.
Reflex is a tightly temperature controlled system and as a result, Reflex pods last much longer than typical pod system pods.