INDUSTRIAL GRADE: 50 lbs tension is based on the direction of tension perpendicular to the contact surface -- reduced by 2/3 if used Horizontally. Whether magnetic hooks can hold 0lb, few pounds,many pounds, your steel is decisive! 1. A thicker Steel: Thin steel means saturation of flux in the magnetic circuit. Excess magnetic flux is wasted in the air and can't be utilized. 2. Thinner painting/no spacer Thick painting will give rise to a great leakage of flux,only a small portion of flux from magnetic hooks can be utilized to provide the attractive force.The thicker the painting, the worse the magnetic force! STEADY WITHOUT DRILLING: This magnetic hooks can be used indoor or outdoor, the school, home, office, workshop, warehouse and garage. Warning Warning and Precaution! It is extremely dangerous to bring a magnet close to a person possessing electronic equipment such as a pacemaker or other types of electronic medical equipment. It may impair normal operations of the equipment and lead to a fatal accident. Keep magnets always from magnetic recording media such as floppy disks, magnetic digital cards, magnetic tapes, prepaid card. If it is placed near to a magnetic recording medium, recorded information may be destroyed. Do not store magnets in places where they are exposed to rain or dust or under conditions in which moisture condensation occurs; Don’t expose to fire or places with high temperature,surface conditions, physical properties, or magnetic properties may change if stored under such circumstances"