Perrin & Rowe Classical Example Shower Layout 11A comprises a shower rose on riser pipe with two handle combination mixer. Shower roses come in three diameters with the 200mm being the most popular. The standard rose has a perforated plate and, when calcification is a problem in hard water areas, specify the Easyclean version with rubber holes. This riser pipe has a 90 degree bend, and is 1600mm in length.