Thanks guys and girls! I originally used 11" flexwatt and it actually caught on fire, or at least started smouldering, against the plastic inside the incubator. I switched to the lower wattage 4" and it's safe now, but I had to scrape up the burned flexwatt and melted plastic and scrape the soot/resin off the inside of the glass. I was at work when it happened, so I'm lucky it didn't torch my condo. You have to be careful with flexwatt.