Unfortunately they did not print on the box there what it is. So if you flip over the hood on the bulb on one end it will be printed on it. It should say either 5.0 or 10.0.Oh!! ??![]()
If it is a 5.0 bulb you want a distance of 8-9 inches to the basking branch below the fixture. If it is a 10.0 bulb then you will need a distance of 11-12 inches to the basking branch below it.... Additionally I would get a 24 inch fixture to go on top of the new enclosure. You really want this to span the width of the enclosure.