Here is a Photo of the Inside of a Flasher, the flasher USE2WALK is using, has a thin, lets say .20 thousands thick Tungsten bar with the Resister wire wrapped around it. It is getting hot quickly, and makes and breaks Contact Fast.
Now if he goes to a Heavy Duty Flasher with lets say .50 thousands Thick Tungsten bar it takes longer to heat up and cool off, making and breaking Contact Slower.
When you push the turn-signal Lever down, the flasher connects to the turn-signal bulbs by way of the turn-signal switch. This completes the circuit, allowing current to flow. Initially, the spring steel does not touch the contact, so the only thing that draws power is the resistor wrapped around the Tungsten Bar. Current flows through the resistive wire, heating up the smaller piece of spring steel and then continuing on to the turn-signal lights, making them flash on and off.