Medium celebration lamp is a lamp that can be won on Treasure Hunter. When used on a regular skill, it gives experience equal to a medium prismatic lamp, plus 5% of the experience provided to the selected skill in all other skills, and the lamp is destroyed. Elite skills work similarly, but you get 10% of the experience you would have gotten if the lamp was used on that skill. This means that the higher the skill you select, the more experience all of your other skills will get. Every 10 lamps boost the experience gained by 2% more, up to a max of 20% global and 10% for the selected skill. It is destroyed after rubbing.
Additionally, players can inspect the lamp to toggle on getting experience in combat skills. This is toggled off by default.