You must be logged in and verified to contact the designer.
This is a structural part which can be used in any scale. It is the hemi-spherical cap designed to be used in conjunction with 4" Schedule 40 pipe which can be purchased at most hardware and construction suppliers such as Home Depot, Menard's, and Lowe's. This part is designed to match the outside diameter of the pipe with effectively no overhang.
This is not a pipe fitting to be used in pressurized systems, it is for modeling and cosmetic purposes only. This part has 1.5mm walls and is not designed for structural applications requiring strength.
4" Schedule 40 pipe has an outside diamter of 4 1/2".