Procyon Rear Bike Light

What it is

The Procyon is Proviz's entry-level rear light — and 'entry-level' here means stripped to exactly what a commuter or weekend rider actually needs. It weighs 26 grams. It charges over USB. It clips to a seat post, a bag strap, or a helmet strap. That's the pitch, and it largely delivers.

Build and size

At 45 × 38 × 25mm, the Procyon is roughly the size of a matchbox. The casing is a mix of metal and plastic (PS and PMMA per the spec sheet), which feels solid enough for the price without adding meaningful weight. The quick-release mounting bracket snaps on and off cleanly — useful if you're commuting and want to pocket the light at the office rather than leave it on the bike.

The IPX-4 waterproof rating means it handles rain and road spray without issue. It is not submersible, and we wouldn't recommend riding through standing water with it, but for real-world British-weather commuting or a wet trail descent, it holds up.

Modes and visibility

Three modes: Full, Low, and Flash. The LED is a CLM2B — a single-emitter setup that punches above what you'd expect for the price. Flash mode is the one you'll use most in daylight urban riding; Full is better for unlit paths where you need consistent illumination behind you rather than a strobe. We'd have liked a second flash pattern or a slower pulse option, but at this price bracket, three modes is the norm.

Battery life

The 80mAh lithium-ion cell gives you up to four hours on full brightness, longer on flash. That's enough for most commutes with room to spare, but if you're doing multi-hour evening rides, you'll want to top it up religiously. The USB cable is included, which is a small but appreciated touch — you shouldn't have to source your own for a $15 light.

Mounting versatility

This is where the Procyon earns its keep beyond pure cycling. The clip system works on a seat post, yes, but also genuinely on a rucksack strap or a helmet — which matters if you're a run-commuter who walks the last half-mile, or if your bike setup doesn't have a clean mounting point. We've seen lights that claim multi-use and deliver on none of it; this one actually works on a bag strap without flopping around.

Who it's for

Urban commuters who want a light they don't have to think about. People who run and ride. Anyone building out a bike kit on a budget who needs a rear light that isn't embarrassing. It's also a sensible backup light to throw in your bag when your primary setup runs out of juice mid-ride.