**Rewritten Description:** Please note: Slight color variations may occur but do not affect functionality. - **7-Step ECG Ruler**: Follows a scientific interpretation method, offering clear reference points for key ECG analysis steps. Helps quickly assess ECG readings. - **Portable & Transparent**: ID-sized and compact, fits easily in badge holders, pockets, or kits for quick access in clinics, classrooms, or workplaces. - **Easy-to-Read Guide**: Measures heart rate and checks PR interval, QRS complex, QT intervals, and elevation/depression. Ideal for ID badges. - **Durable Material**: Made of sturdy, transparent plastic for long-lasting clarity and easy cleaning. **Color**: As pictured **Material**: Plastic **Package Includes**: 2 �� ECG 7-Step Rulers 2 �� Blue boxes *Note: Colors may vary slightly due to lighting or screen settings. Slight size variations (1-3cm) are possible.*