Genuine Hamamatsu (made in Japan) component, supplied with data sheet  S1787-04 is a high-performance, high quality plastic package photodiode that offers low dark current. 
 
The plastic package used is light-impervious, so no stray light can reach the photosensitive area from the side or backside. This allows reliable optical measurements in the visible to near infrared range, over a wide dynamic range from low light levels to high light levels. 
 
Photosensitive area 2.4 x 2.8mm. 
Package size 8 x 6 x 2.2mm (exc leads). 
Vr Max 10v. Dark current 10pA max. Spectral response is 320-730, peaking at 560nm. 
 
This photodiode is ideal for work in the visible light spectrum. Possible applications include 
 
A replacement for visible light photodiodes AKA silicon blue photodiodes as used in many cameras and other photographic equipment.
Light meters 
Lux meters 
Robotics and Ai
Any device for reliably measuring the visible light spectrum as well as general use.
 
DATA SHEET
https://www.hamamatsu.com/eu/en/product/optical-sensors/photodiodes/si-photodiodes/S1787-04.html