Waxed Copper Bulb is a copper light block added to Minecraft in version 1.21, crafted by combining one Copper Bulb with one Honeycomb in a shapeless recipe that yields one Waxed Copper Bulb. The honeycomb coating locks the copper at its current, unoxidized stage permanently, so Waxed Copper Bulb keeps its warm orange tone and full light level 15 output for the entire lifetime of a world. A fresh Copper Bulb emits light level 15 when lit, and waxing is the only way to guarantee that brightness never fades, because oxidation would otherwise dim the bulb through exposed (level 12), weathered (level 8), and oxidized (level 4) stages over time.

As a redstone device, the block works as a compact T flip-flop: a single redstone pulse toggles the light on, the next pulse toggles Waxed Copper Bulb off, and no continuous power is needed to keep the bulb lit. A red dot appears in the center of the block while redstone power is being received, and a comparator reading the lit bulb outputs signal strength 15, which makes the device useful for hidden memory cells and alternating lighting patterns. Waxed Copper Bulb is renewable, requires at least a stone pickaxe to mine (otherwise it drops nothing), and has hardness 3 with blast resistance 6, so the block suits both decorative facades and functional redstone contraptions in survival builds.