This Guardian Equipment 330-12-08RSE-ORG ABS plastic street elbow is used to connect horizontal-mounted shower heads to the supply piping. Available in your choice of orange, green (330-12-08RSE-GRN), or yellow (330-12-08RSE-YEL). The corresponding shower head is item # AP450-032ORG.
For metal street elbows to fit metal shower heads see item # 300-08SE.
A parts diagram for Guardian showers is also available.