A miniature LDR in a TO-18 package. Silonex NSL-19M51
This device contains cadmium sulphide which is restricted under the RoHS regulations and is not RoHS compliant.
Body dimensions: 4.4 x 3.8 x 1.7mm
Lead pitch: 2.5mm
Max power dissipation: 50mW at 30 deg C
Max voltage rating: 100V DC or peak AC
Min dark resistance: 20M
Resistance @ 10 lux: 20K
Typical resistance @100 lux: 5K