Many different characteristics must be blended together to make a good camming unit:  holding power, ease of use, range durability, weight, price, etc.  Many of the characteristics are antagonistic.  For example, some holding power is usually sacrificed to get increased range or vice-versa.  Each manufacturer chooses which properties to emphasize in their cam design and which can be compromised.  The bottom line is, if your cam pulls out, the other properties don't matter.  That's why we design our camming units to maximize holding power.
      When a load is applied to a camming unit, the cams respond by pushing out against the walls of the placement.  Three variables determine how much force the unit will hold:  how hard the cams push out against the walls of the placement (outward force), how well the cams grip the walls of the placement (friction), and how well the rock on the walls of the placement hold up to the pressure of the cams (rock strength).
     The angle at which the cams push out against the walls of the placement is referred to as the cam angle.  Cam angle is critical because the more the cams push straight out against the walls of the placement (smaller cam angle), the greater the outward force is and the stronger the placement is.  Imagine stemming in a chimney with blank walls.  The more you push straight out on your feet, the more secure you feel.  As you try to move up, you begin to push at a downward angle.  The steeper that angle becomes, the more you rely

on the friction of your shoes, and the less secure you feel.  Unfortunately, the more the cams push straight out, the less range they have.  Range is increased by making the cams push at a more downward angle (greater cam angle), which decreases the outward force.  The trick is to optimize the angle to have sufficient range and maximum holding power.
     Given that all cam materials currently in use have about the same coefficient of friction, the only way to increase the grip between the cam faces and the rock is to increase the surface area.  Wider cams grip the rock better just as wider car tires grip the pavement better.
     The rock strength accounts for what is probably the most common mode of failure in the real world.  Even in very hard rock types, it is not uncommon for the surface layer of rock to pulverize under the force of the cams, forming a loose layer (like ball bearings) which allows the cam to pull out.  Wide cam faces spread the load out and greatly reduce the chance of breaking the rock on the walls of the placement.
     Metolius cams have a slightly smaller cam angle than most manufacturers', so the cams are generating more outward force for a similar load.  We sacrifice a little range to do this, but we think it's well worth it.  We also increase the surface area of the cam faces to increase the grip.  We have the widest cam faces on the market, far and away.  This has the added benefit of spreading out the force on the rock, reducing the chance of failure due to rock breakage.