TO-39 /  TO-5 housing
Competitive cost version Designed for motion control

The LHi 874 and LHi 878 pyroelectric infrared-detector series are the standard dual element design recommended for all variants of motion control. They include a dual element pyro-electric ceramic with FET in source follower connection. The LHi 874 is available as TO-39,  whereas LHi 878 detector is available  in TO-5 housing with standard infrared filter. They both offer high responsivity with excellent common mode performance (match) and low noise at steady state and temperature changes.
For both variants RF improved options are available.