Who needs this Cyclists, bicycle mechanics and bike enthusiasts who prioritize correct, ergonomic saddle positioning during rides or maintenance. Shops and home mechanics who perform fine adjustments and need repeatable, accurate results. Key benefits Faster, more accurate saddle setup: combine visual bubble-vial leveling with digital angle data from your phone to reach correct seat angle and height reliably. Better comfort and performance: precise alignment reduces discomfort and improves pedaling efficiency. Consistent service results: horizontal calibration system and millimeter-level accuracy provide repeatable setups across different bikes and riders. What it does 3D-printed polymer leveling tool designed to align bike saddles and frames. Built-in bubble vials for immediate visual leveling. Smartphone app compatibility for precise angle measurements and verification. Horizontal calibration system delivers accuracy to the millimeter for true, flat reference across the bike. Compatibility and performance Works with road bikes, mountain bikes and indoor bike setups (turbo trainers / indoor trainers). Material: durable 3D-printed polymer for stable reference without adding excessive bulk. Measurement approach combines mechanical (bubble vial) and digital (smartphone angle) methods so you can choose the level of precision you need. Practical applications / use scenarios 1) Garage or repair shop: fine-tune saddle angle and fore/aft position during a service to ensure every customer leaves with a correctly aligned bike. 2) At home or outdoors before a ride: quickly check and correct saddle angle and balance for improved comfort on long rides. 3) Indoor trainer setup: calibrate bike position on a trainer to match outdoor geometry for training accuracy and injury prevention. What makes it stand out Dual approach: integrated bubble vials for quick visual checks plus smartphone compatibility for precise angle readings. Horizontal calibration system engineered for millimeter-level accuracy, helping avoid guesswork when adjusting saddle height and angle. Designed for the specific needs of cyclists and mechanics rather than generic leveling tools. Usage notes Use the bubble vials for fast preliminary alignment and the smartphone angle readout for final verification. Compatible with standard bike geometries across road, mountain and indoor setups; follow your preferred fitting protocol for fore/aft and tilt adjustments. Trustworthy and practical Straightforward tool focused on accuracy, repeatability and ease of use to support safe, comfortable and efficient bike setups.