Because you referenced the code , it is crucial to understand what this mark signifies:
While "A112.18.1M" looks like a specific model number, it is actually a (ASME A112.18.1M) that appears on almost every shower head sold in the U.S. and Canada. Because of this, "reviews" for this specific number often vary wildly because users are describing completely different products from brands like Peerless, Delta, Moen, and Glacier Bay. peerless a112.18.1m shower head
It threads onto any standard 1/2-inch NPT pipe arm. You do not need a plumber. You need a roll of Teflon tape and sixty seconds. Because you referenced the code , it is