The only other assembly needed to the Flowtron was inserting the octanol cartridge, which slides conveniently into the cartridge holder on the bottom in the unit. The cartridge lasts about 30 days and fees about $15 for any substitute 3-pack. Say goodbye to pesky flies and biting mosquitoes Using https://rafaelsiufs.uzblog.net/flowtron-bk-40d-electronic-insect-killer-can-be-fun-for-anyone-42900519