Quick search here for Dwyer Flow returned nothing similar to this...
One of my trade publications posted an ad for a Dwyer Instruments paddlewheel-style flow indicator with output sensor and visual sight indication. Solid brass body w/ tempered glass window and Red PBT paddlewheel. Supposedly made of UV-Stabilized materials for outdoor use.
Dwyer Sensor Line
SFI-100T (Advertised Sensor)
FYI --->These are also pricey.