The max cape is a cape available to players who have attained at least level 99 in all 27 skills (it does not require level 120 Dungeoneering or Invention). It is sold by Max in Varrock and by Elen Anterth in the Max Guild for 2, 673, 000 coins. It has an emote which shows off the player's expertise in each skill. The minimum total level a player needs for max cape is 2, 673. When purchased, it comes along with a corresponding hood. The minimum amount of experience required to wear this cape is 374, 968, 717.
Equipping the cape will unlock the Maxed [Name] title, which has the same requirements as the cape. This title can be used without wearing the cape once unlocked, and will re-lock when the cape is unable to be worn. The cape also offers a teleport to the Max Guild by right clicking it - arriving next to the skill portals inside the guild garden. Chatting with Elen Anterth provides an option to toggle the Max Cape teleport between the garden and within the tower. Players need to wear their cape after (re)obtaining it in order for Elen Anterth to appear inside the Tower.
There are two ways to buy the cape and hood, the first way is by locating Max. He will move from location to location in eastern Varrock. Once spotted, Max will offer to sell qualified players this cape for 2, 673, 000 coins, which is 99, 000 coins (the price of a typical skill cape) times 27 (the number of skills). The second way is to simply just buy it from Elen Anterth in the Max Guild.
The colours of a max cape can be customised by using the option in the right-click menu of the cape. In the Skillcape Customiser interface, players have the right-click option on the either of the four colour palettes to get or set a certain colour via the HSL colour algorithm (hue, saturation, and luminosity).