1. Material: main body PP plastic + spring steel spring 2. Strength value: 5-60kg 3. Weight: about 135g 4. Spring diameter: 3mm 5. Dimensions: length 11 cm, width 2.2 cm, height 16 cm 6. Automatic counting, the number of exercises is clear at a glance, can be cleared and reused 8. The knob can easily adjust the intensity to meet your different needs