What this product does A 3D-printed polymer leveling and alignment tool that gives millimeter-accurate horizontal calibration for bikes. It is designed to help you set and check saddle tilt and alignment across road bikes, mountain bikes and indoor trainer setups. Why you need it Consistent, repeatable alignment reduces discomfort and improves handling. This tool removes guesswork by providing a precise reference for saddle position and bike balance so adjustments are fast and reliable. Key benefits Millimeter accuracy: engineered horizontal calibration ensures precise alignment across different bike types and setups. Durable 3D-printed polymer: robust plastic construction withstands shop and outdoor use while staying lightweight and easy to handle. Integrated bubble vial + smartphone compatibility: built-in spirit level for quick checks and seamless use with mobile angle-measurement apps for more detailed readings. Adjustable and versatile: designed to work with road, mountain and indoor trainer configurations so you can carry one tool for multiple bikes. How it solves common problems Eliminates subjective alignment: gives objective, measurable feedback so you can reproduce settings between rides or bikes. Speeds up setup: quick bubble-vial checks and app-assisted angle readings reduce trial-and-error adjustments. Works in any workspace: reliable calibration whether you’re in a garage, a pro shop or out on the roadside. Compatibility, materials and performance Material: 3D-printed polymer/plastic engineered for durability and dimensional stability. Performance: millimeter-level horizontal calibration accuracy; integrated bubble vial for instant leveling; compatible with common smartphone angle apps for precise angle measurements. Fit: suitable for use on road bikes, mountain bikes and indoor trainer setups without need for additional electronics. Typical use scenarios 1. Pre-ride setup in the garage: quickly verify saddle tilt and fore/aft balance before a long ride to ensure comfort and consistent power delivery. 2. Workshop fine-tuning: bike mechanics use the tool to set repeatable saddle angles and document settings across customer bikes. 3. On-the-road checks: lightweight and portable for roadside or trailside quick checks to restore preferred alignment after transport or adjustments. Practical notes Use the integrated bubble vial for fast visual leveling, then pair your smartphone angle app if you require numeric angle readings or wish to save measurements. The tool is intended as a positional and leveling aid; follow standard torque and fastening procedures when locking saddle rails and seatpost clamps. This tool provides a simple, precise and durable method to achieve consistent bike seat alignment across multiple bikes and environments, combining a practical mechanical level with modern smartphone-assisted angle measurement.