They can be bought in various test curves, which correspond to how stiff the tip is (often measured in ounces.) The lower the test curve, the less stiff the tip is (i.e. the less weight required to bend the tip.) The test curve of the tip should be carefully considered as it could drastically impact on the bite detection/playing of the fish and should relate to the type of fish targeted and weather conditions. As a general rule, it is desirable to fish with the lightest tip possible; that means the tip with the lightest test curve. This is because the lighter and more flexible the tip, the more sensitive and accurate the bite detection it provides. One of the basic skills in quiver tip fishing is selecting the correct weight of the tip to match the target fish, having regard to the type of water and the prevailing weather conditions. For example, if British roach are being targeted on a stillwater in flat calm conditions, a quiver tip of a test curve of no more than an ounce would be a good choice. Alternatively, fishing for a strong aggressive fish like the British barbel in a fast-flowing river would require a heavier tip, possibly of three ounces or more - a lighter tip would be permanently bent round by the flow of the water, eliminating bite detection, and playing a strong fish would probably break it completely.