Screw clamps. Screw clamps are types which use a screw mechanism to adjust the jaws and clamp a workpiece in place. The types which are found in the screw clamp category include G clamps (also known as C clamps), F clamps, edging clamps, wooden hand screw clamps and rack clamps.
Dry drowning usually happens soon after exiting the water, but with secondary drowning, there can be a delay of up to 24 hours before the person shows signs of distress. Both can cause trouble breathing and, in worst-case scenarios, death.
One that jumped out at me is that on any given year, there is one drowning of a child for every 11,000 residential pools in the United States. What this means is that in a country with 6 million pools, roughly 550 children under the age of ten drown each year. Another more recent study not in the book points out that 10 people a day die from drowning in the United States.