Heinrichs Weikamp

Heinrichs Weikamp OSTC 4

The higher-resolution flagship of the open-source OSTC line, with full CCR PO2 monitoring.

Open BLE sync (libdivecomputer)

Syncs wirelessly with third-party apps (Subsurface, Currents, etc.), not just the manufacturer app.

Heinrichs Weikamp OSTC 4
$900
Released2016
Max depth rating120m
AlgorithmBühlmann ZHL-16C with optional gradient factors
Air integrationnone
Wireless—
DisplayHigh-resolution color display
Batteryrechargeable
Digital compass—
Gas typesair, nitrox, trimix
Gas switches—
CCR capableYes
Pros
  • High-resolution color display, sharper than the OSTC 2/3
  • Full closed-circuit rebreather support with constant PO2 monitoring
  • Open-source firmware with active community development
Cons
  • Price converted from EUR list pricing, may not reflect current US retail
  • 40-hour dive-mode runtime is shorter than AA-battery competitors
  • Niche brand with a smaller dive-shop support network than the majors

The OSTC 4 is Heinrichs Weikamp’s higher-resolution flagship, built on the same open-source Bühlmann/GF firmware as the rest of the line but adding full CCR constant-PO2 monitoring and a sharper color display for trimix and rebreather divers.