Step 3: No Hub Coupling from the plumbing dept
Next a No Hub Coupling from the plumbing dept to make a tight sleve to hold the light bulb in place and make it water (tight??). You are gonna pull the rubber part out and cut it in half but leaving the middle rim on one side then trim it to abot 3/4" to an inch total width. (I hope that makes sence once you start cutting it)
No Hub Coupling 1 1/2" to 1 1/2"