The Weslo Company makes a wide variety of cardiovascular equipment, including a treadmill. The safety key for the Weslo treadmill is attached to a string and clip, which attaches at the waist. The treadmill with turn off, when the key is pulled out. This will keep you safe from injury, in case of a slip or fall while using it. Unfortunately, the safety key is small and easy to lose; therefore, a reliable replacement key will allow you to maintain safety while operating the device.
Draw on a sheet of hard plastic, that is 1.5 mm (1/16 inch) thick, a rectangle that is 2.5 cm (1 inch) wide and 7.5 cm (3 inches) long. Use your ruler and pencil to trace these lines.
Cut out this design with scissors, or a sharp Stanley knife. Make sure you cut away from the body to avoid injury.
Use a hole-punch, or carve out a hole on the plastic rectangle. The hole should be located 3 mm (1/8 inch) away from one end lengthwise -- and in the middle of the plastic width-wise.
Cut a 90 cm (3 foot) piece of solid, durable string, and tie a solid knot through the hole -- to secure the string to the safety key.
Tie the other end of the string to a safety clip and secure with another firm knot.
You may need to alter the length of the string and length of the key to better fit the key to your stride length while running and your treadmill.
Test the distance for where the key will pull out by stepping back on a non-moving belt with the key and clip attached until the key pulls out. If you are on the very end of the treadmill, you should shorten the string on the length of the key.