PK3-B2 : Round 20mm photo sensor bracket for PK3 sensors, LxWxH : 32x14x95mm, fitting as follow items 

1. Photo Sensors : PK3-DU20NP, PK3-DU20NPB, PK3-DU30NP, PK3-DU30NPB, PK3-DU50NP, PK3-DU50NPB