O. Pen Sesh

The O.Pen Sesh stands apart from basic 510 batteries through its session mode. Double-pressing the fire button starts a 15-second preheat cycle at low voltage, distributing viscous oil across the coil. After that, the session runs for a preset duration without holding the button. This is convenient for longer draws since your thumb stays free. Three voltage levels — 2.4 V, 3.2 V, and 3.8 V — cover thin to thick oils. The active level is shown by the LED color.

The Sesh uses a magnetic 510 adapter that sits between the cartridge and battery. Instead of screwing the cartridge directly in, it threads onto the adapter which then snaps magnetically onto the device. This protects the 510 threading from wear and makes swapping cartridges on the go faster. The 280 mAh battery is on the smaller side but covers a day of casual use. Charging through Micro-USB takes about 25 minutes. At 10 cm long and pen-shaped, the Sesh fits discreetly in a jacket pocket.

The O.Pen Sesh uses the 510 thread found in over 90 percent of common cartridges. Standard cartridges up to twelve millimeters in diameter fit without an adapter. Thicker CCELL cartridges at 13 or 14 millimeters also sit securely but extend slightly past the housing ring. Three voltage levels let you adjust for thin distillates at low voltage and thicker oil cartridges at higher voltage. Ceramic coil cartridges work best at the middle setting since they heat more evenly than at full power.

• O. Pen