The VRK-LH1 is a Development Module based on the TS4231 IC from Triad Semiconductor which can decode the laser sweeps and pulses from generations 1 & 2 of the Steam VR Lighthouse Tracking System.
This is a Pre-Order for the second Batch of manufacturing.
The Photo Diode on board is the BPW 34 S-Z.
This module allows for use with many micro controllers, leading to rapid software development for Steam VR Lighthouse Tracking.