1. Box contents: The set includes 2 pieces of bicycle front wheel riser blocks and 1 piece of bicycle quick release. Riser block dimensions: 22.5 × 11 × 6 cm / 8.86 × 4.3 × 2.36 inches. Compatible with most bicycle sizes. 2. material: The front wheel support roller trainer is crafted from grade technical plastic, offering lightweight, strength, stability, and exceptional durability. Integrated nonslip rubber pads prevent slipping while safeguarding your floor from scratches. 3. Assisted bicycle training: During cycling workouts, hand fatigue may occur when training on surfaces uneven with the bike's position. This front wheel riser elevates your front wheel to provide a natural riding posture. 4. Bicycle quick release: This bicycle spike features a steel quickrelease bar, suitable for mountain bikes and indoor bicycle trainers. It serves as a versatile tool for both indoor and outdoor maintenance.