Lasco 2″ Thread x 1-1/2″ Thread PVC Reducer Bushing, 439-251

This is the Lasco 439-251, a PVC reducer bushing that steps a 2 inch threaded connection down to 1-1/2 inch threaded.

Reducer bushings are what let a pool plumbing run join parts that were not built to the same size. Equipment ports and pipe sizes rarely all agree on one pad, and this fitting handles the most common mismatch of the two residential sizes without cutting and reworking the line.

Because both ends are threaded, the joint stays serviceable. You can break it later for equipment work instead of sawing through solvent welded pipe. Check the thread on each end against what you are joining before you plumb it in, use PTFE tape or a PVC rated sealant, and take it up hand tight plus a small amount only.

One thing worth planning around: every reduction narrows the passage. Put it where the equipment actually needs the smaller size rather than partway along a long run where it just costs you flow.