The SDP8105 series, from Honeywell, are from their SDP series of silicon photodarlingtons. They are in 3mm (T-1) through-hole plastic packages. The SDP8105 series have a black plastic lens which provides a daylight filter, reducing effects of visible ambient light.
Features of the SDP8105 photodarlington:
T-1 (3mm) black plastic package
Through-hole mounting
Acceptance angle: 20°
Operating temperature: -40 to +85 °C