While strength and capacity go hand in hand, they are somewhat different considerations. A good, strong monopod is one made of quality materials and having sturdy leg sections. Most monopods are made of aluminum or carbon fiber. Aluminum is tough, light and corrosion resistant. Carbon fiber is lighter than aluminum and also stronger. When considering strength, be aware that you can get a monopod that is so strongly built that it no longer serves you well in the weight category. As for capacity, you want a monopod that will hold at least twice the weight of the heaviest equipment (camera, lenses, spotting scope) you plan to use it to stabilize. Weight capacity for most monopods will be listed in the product's specifications.