Campbell Scientific Hydro-Wiper-D Manual from ZebraTech - Manual (Page 3)

Hydro-Wiper operation manual
Zebra-Tech Ltd 2
Installation
The OBS3+ is mounted in the clamp at the front of the wiper, with the
optical window facing directly away from the Hydro-Wiper. The
OBS3+ should be positioned so that the brush sweeps across the
whole surface of the optical window (Photo 1).
Photo 1. Mounting the OBS3+ in the Hydro-Wiper clamp