Mcalpine STW19

McAlpine STW19 refers to a 19mm water seal shower trap designed for modern shower trays. It’s part of McAlpine’s STW series, which includes multiple flange and finish options. While the exact “STW19” model number doesn’t appear directly in listings, the product family matches the 19mm water seal traps such as STW1, STW3, STW5, and STW7 — all of which share the same core specifications.

You will need to either keep or get a new O ring

Print with tree supports, and starting from the castellated section.