Today 12/04/21, bulbs received 11/16/21. I have 2 outdoor lights that use 12 volt 20 watt T3 bulbs. To date I have used 10 of them. They burn from 5 p.m. to 6 a.m. Apparently they last about 40-70 hours and all open in the same place (in the middle of the thread). They did not open sharply (no burn marks inside the glass).