Easy observation: The rotating observation mirror for coffee extraction provides a clear view of bottomless espresso extraction and lets you monitor your brewing process with ease. 360-degree rotation: The espresso lens mirror features a 360-degree rotatable joint, enabling quick angle adjustments to observe flow and crema development accurately. Purpose: Designed to facilitate monitoring of espresso extraction from a bottomless portafilter, helping you assess shot quality more reliably. Portable: Lightweight and easy to transport, this mirror is suitable for both indoor use and outdoor setups. Use scenarios: - Home setup: Dial in grind size, dose, and pull time by watching extraction dynamics directly. - Barista training or cafe workflow: Demonstrate and practice proper extraction techniques with real-time feedback. - Outdoor or mobile service: Observe shots during events or catering without bulky equipment, maintaining efficiency and quality.