A downlight apparatus may include a canister with a canister body and a canister base comprising a female helical thread defined as an engagement host. The downlight apparatus may also include a lamp including a lamp body and a male helical ridge, defined as a lamp ridge. The lamp ridge includes a platform that extends distally from a root of the lamp ridge to a distance ranging from 2 to 20 times greater than the distance between the root and the crest of an Edison screw base thread. The lamp and the canister are structured to secure to one another when the lamp engages with the engagement host.