features a hidden and detachable lithium battery, a high-rigidity aluminum alloy frame, and a four-link suspension for a smooth and comfortable ride. Features: Hidden and Detachable Lithium Battery: The e-bike features a hidden and easily removable lithium battery that can be charged directly on the bike or separately. Charging time is 7-8 hours. Aluminum Alloy Frame: The bike's frame is made of 6061 aluminum alloy with a four-link suspension. It undergoes high-temperature shrinkage treatment for higher rigidity and lighter weight. Four-Link Suspension: The four-link suspension reduces vibration for a smoother and more comfortable ride. Intelligent Controller: The reliable and precise I-drive sine wave vector control system allows for quick control of the motor, battery, sensor signals, and combination switches. Full-Color Display Screen: The YG90 model features a full-color LCD display with an IP54 waterproof rating. It provides a visual icon display for quick understanding of the vehicle's status and faults.