Southland 3/8 in. x 3 in. Galvanized Steel MPT Nipple 562-030HN - The Home Depot
Amazon.com : 4 Way Flat Edge 1 3/8" Canopy/Batting Cage Fitting (FVF4) - Fits EMT Pipe or Chain Link Fencing Top Rail That has an Outer Diameter of 1 5/16" : Patio, Lawn & Garden
RELIABILT 3/8-in x 1/4-in Galvanized Reducing Coupling in the Galvanized Pipe & Fittings department at Lowes.com
Pipe Fitting - Galvanized Steel - Instrumentation - Reducing Hex Nipple - 3/ 8" x 1/4" NPT Male
Smith Cooper 150# Galvanized Iron 3/8 in. Banded Coupling - Threaded - John M. Ellsworth Co. Inc.
Evecad 6PCS 1-3/8" x 1-3/8" End Rail T Clamp, Galvanized Steel Panel T Clamp, Chain Link Fence Parts, Chain Link Fence T Clamp 1-3/8" OD Pipe, Bolts & Nuts Included - Amazon.com