The race clock built for finish lines, start lines, and every chute in between.

Most race clocks force a tradeoff: bright enough for daylight but short on battery, or all-day battery but unreadable at the finish. jClock removes the tradeoff. The LED matrix runs at 3,200 cd/m² behind an anti-glare panel, and adaptive brightness keeps the display legible from open noon sun to night track lighting — without burning the battery down before the last athlete crosses.

The internal LiFePO₄ battery is rated for a full marathon at normal brightness and significantly longer at half brightness. You charge between events, not during them. Operating temperature is −10 °C to 50 °C, and the IP54 rating means the same clock that runs a cold spring marathon in the rain can run a summer triathlon under direct sun.

The same hardware, configured for the day. Count up for the gun-start road race. Count down for the wave-start triathlon. Hold a fixed time of day for the Olympic-distance turnaround. Cue waves for an obstacle race. Light a chute for the broadcast camera. The control surface is identical across all of them, which means your timing crew learns one device and runs every race on the calendar with it.

jClock is engineered for the full range of timed athletic events — road racing from 5K to ultramarathon, track and field at every distance, triathlon and duathlon, open-water swim, cycling, and obstacle racing. One clock, configured differently per event.

For timing companies running large fields, jClock exposes a typed REST and WebSocket API alongside the consumer-friendly Bluetooth and Wi-Fi paths. POST a countdown configuration to the device from your event platform. Subscribe to the live state via WebSocket. Token-scope each operator. Audit the trace.

Each clock holds up to four simultaneous operators, and hand-off between Bluetooth, Wi-Fi, and API is glitch-free. Latency is roughly 8 ms over BLE, 10–20 ms on a clean LAN, 40 ms over the open internet.