The PAX 4, sold as the PAX FOUR, beats the PAX Flow, 8.9 to 8.1, and leads in every one of our five score categories. It's lighter and cheaper, and PAX rates it for more sessions per charge. Pick the Flow if you want a wide-open draw, a bigger 0.4 g oven and the easiest cleanup in the PAX line.
Key differences
- Heating: both are hybrids with one button and no app. The PAX 4 has four heat modes, the Flow four plus a hidden fifth Bong Mode.
- Weight: 125 g for the PAX 4, 135 g for the Flow.
- Heat-up: about 45 seconds for the Flow and 55 to 70 seconds for the PAX 4, per PAX's quick-start guides.
- Oven: about 0.3 g in the PAX 4, up to 0.4 g behind the Flow's magnetic side door.
- Draw: fixed and fairly tight on the PAX 4, wide open on the Flow.
- Battery: PAX rates the PAX 4 at up to 5 sessions and the Flow at about 3.
- Warranty: 2 years on both, rising to 3 on the PAX 4 and 4 on the Flow when you register within 30 days.
- Price: $250 US list price for the PAX 4 against the Flow's $350 launch price. PAX has since cut the Flow's price, so check the live price boxes above for today's gap.
Vapor and draw
The PAX 4 scores 8.4 for vapor quality against 8.0, a smaller gap than the overall scores suggest. In its lower modes it's a sipper, with light vapor where individual terpenes come through cleanly. Push to modes 3 and 4 for denser clouds, and PAX rates this heater at up to 50% more vapor than earlier models. PAX labels the four modes by petal color (purple, green, yellow, orange) and by feel rather than degrees, so you pick an experience, not a number.
The Flow's strength is the draw, since its wider vapor path handles slow sips and full lung pulls without a fight. The PAX 4 stays relatively tight in every mode, which suits PAX's classic sipping style but not everyone. The Flow also extracts evenly, leaving our spent cannabis an even coffee brown with no mid-session stir.
Our heating methods explainer covers how hybrid heaters like these two differ from older conduction PAX models.
Heat, size and carry
The PAX 4 scores 9.8 for portability against 8.5, a gap second only to value in this matchup. At 125 g and 107.5 mm tall, our black unit all but disappeared in a closed hand. The Flow is only 10 g heavier, but its aluminum shell runs hot during longer sessions.
After 6 to 8 minutes on the higher settings, the Flow got genuinely uncomfortable to hold. PAX now recommends its silicone grip sleeve, and that must-have sleeve takes some shine off an otherwise polished vape.
Battery and charging
PAX rates the PAX 4's 2800 mAh battery at up to 5 sessions or 50 minutes of heating. The Flow's 2000 mAh battery is rated at about 3 sessions, or roughly 30 minutes. That's the Flow's weakest spot, and it trails most portables at its price.
The Flow does charge faster, filling in about 40 minutes on a fast charger against about 90 minutes for the PAX 4. Both use USB-C, and neither lets you vape while plugged in.
Loading, cleaning and value
Both run on one button, and the PAX 4 edges ease of use, 9.5 to 9.0. Its funnel-shaped oven makes loading tidy and tapping out spent cannabis easy, with a full clean every 3 to 5 sessions. The Flow's side door opens the whole vapor path to a cotton swab, which makes it the easiest PAX to clean.
The Flow's hidden Bong Mode holds higher heat for up to 5 minutes with lip sensing off, a nice touch for water pipe sessions. Unlock it by cycling through all four regular modes twice until the petals glow multicolor. Otherwise, the PAX 4 wins on value, scoring 8.0 against 6.5 at a lower price. It also holds the brand's spot in our best portable vaporizers ranking, where the Flow misses out.
Which should you buy?
- Most buyers: the PAX 4.
- Pocket carry: the PAX 4.
- Longest time between charges: the PAX 4.
- Open, airy draws: the PAX Flow.
- Bigger loads: the PAX Flow, with its 0.4 g oven.
- Easiest cleaning: the PAX Flow.
- Bong Mode fans: the PAX Flow.
- Upgrading from a PAX Plus and happy with its draw: the PAX 4 (PAX 4 vs PAX Plus).
- Upgrading because a PAX Plus or PAX 3 draw felt tight: the PAX Flow (PAX Flow vs PAX Plus).
