1 package will secure 1 or 2 computer systems. Unless the surface is old and flaky. Unless surface is absorbent, i.e. pottery, newspaper or untreated wood. Non-toxic and contains no hazardous substances. No damage to your skin.
Weight varies depending on base size of object.
You can secure computers and monitors, fax machines, etc. with no problem. The more you use, the better it holds. Stick up posters on walls, remove lint from clothing, secure photographic props. Use it to keep pictures straight and secure so they won't bounce off during an earthquake. Use it instead of scotch tape, pushpins, staples, or tacks because it won't leave ugly tape marks or holes on your walls or finish.