1-1/2 in Merchant Steel Coupling, Sch. 40 Galvanized Pipe Fitting, Class 150 - GP130112 - Hi-Line Inc.
Horiznext npt 1/2 (means the inner diameter of the thread is 3/4 inch) cast female taper threaded pipe coupling, stainless steel 304 coupler for mush tun cooler and shower hose, 2 pcs - Amazon.com
316 Stainless Steel, 2 1/2 in x 2 1/2 in Fitting Pipe Size, Coupling - 1RTE2|4307001172 - Grainger
Guillemin DN 65 Stainless Steel Coupling G 2 1/2'' Female Threads With Lock | Tameson.com