A Medium XP lamp (Construction) is a fairly common prize from Treasure Hunter. Rubbing the lamp grants the player a definite amount of Construction experience scaled to their Construction level, after a confirmation. Freezing the Construction category on Treasure Hunter will remove these lamps from the list of possible rewards. These lamps cannot be banked.
The following is an XP table detailing the experience received from this lamp at various levels: Template:LampXP