They can escape easily out of those very easily. They don't work.
For heating any type of enclosure you MUST use a thermostat or a temporary rheostat until you have a thermostat. This makes sure that your snake doesn't come in contact with temps higher than 95*F.
The thermostat just monitors and controls a heat source. So you would have to get flexwatt heat tape or a UTH with a thermostat.