Double Spring Twister Arm Exerciser, 4 In 1 Adjustable Chest Expander-YuJia f54 10-200KG ADJUSTABLEEasily adjust the force with one button and 10-200kg free adjustment. Just one turn can be adjusted, to meet your needs at all different training stages.DESIGN AND SAFETYThe double spring design allows the spring of the power twister to be evenly stressed and will not deform during the operation. ith the adjustable hydraulic arm strength trainer, you could adjust the resistant power exactly fit your strength, so your muscle wont get hurt by trying an over power resistance. Professional micro-rebound, deny violent rebound, completely solve hidden safety risks for safe fitness with no hurt and safe micro-rebound.DURABLE MATERIAlFirm and durable double-layer steel tube material. Hydraulic pressure design, which ensures the structure never get deformed through long term training. The core is a fully sealed hydraulic cylinder, which has a simple structure, reliable operation, adjustable resistance. The leakproof hydraulic cylinder, which passed 100000 endurance tests, could provide adjustable and stable resistant power, which is much better than traditional spring strength training bars.EASY USE AND STORAGEThe buckle of the handle's bottom is easy to store and convenient to carry. The user-friendly designed rear buckle can be fixed after folding. When finish exercising, please rotate the adjusting knob to the minimum level, and then lock the handle with the buckle, the locked strength trainer will take little space. (Ps: dont hold the buckle part, in case the arm machine dropdown and hurt your feet)COMFORTABLE TO HOLDThe unique golden ratio triangle structure, exercise is more stable. Safer adjust the angle. The opening angle is unchanged. The exercise stroke is also unchanged and it is more effective for muscle training. With the adjustable hydraulic arm strength trainer, you could adjust the resistant power exactly fit your strength, so your muscle wont get hurt by trying an over power resistance. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.