A shower arm is a plumbing component that connects the showerhead to the water supply coming from the wall. The "Shower Arm Recta" likely refers to a straight or rectangular-shaped shower arm. Shower arms come in various shapes, sizes, and finishes, including straight, curved, angled, and S-shaped. They are typically made of brass, stainless steel, or chrome-plated metal, and can be either fixed or adjustable in length. The choice of shower arm depends on personal preference and the shower design. A straight or rectangular-shaped shower arm may be preferred for a modern or minimalist look, while a curved or angled shower arm may be preferred for a more traditional or elegant look.