An Adamant helm (h5) is a helmet obtained from the Level 2 Treasure Trails requiring 30 Defence to wear. It cannot be made using the Smithing skill but has stats identical to that of an adamant full helm.
Players typically wear it for its unique design and, along with the other various heraldic helms, is often referred to as a 'bucket helm'. There are also four other heraldic helms made of adamant, each having a different heraldic design. There are also heraldic helms in rune and black with the same designs.