I have found that this particular size bulb is very diffucult to find. This size is also very expensive compared to the other replacement bulbs for the same size Dynatrap which has a different number, both do the same job, same size just a different bulb, one has 2 prongs on each end the other bulb has one end w/ 2 prongs & the other end has a plastic (1) tip, this is the $40 bulbs. The only difference between the two Dynatraps is the year they were made. The Dynatrap that takes #32020 bulbs set of 2is $40.00 the Dynatrap #32050 bulbs set of 4 bulbs is around $20.00, BIG difference!!!