Though it's not an identical drop table in terms of RuneScape gold value to Medium Casket and is a hard difficulty, you also have the chance of winning the extremely rare table. You can get a wide range of extremely expensive items including 3rd Age Equipment and Gilded Parts with the value of hundreds, or even thousands of millions (like 3rd Age Platebody). Additionally, items from the exclusive drop table are extremely valuable as they come with four items that have a value of more than one million gold. On top of that you will get more roll for rewards with a hard Clue than with a Medium One which means that in general they will yield better rewards.
Just like with the previous box, you have a chance to win uncommon and extremely rare items with the value of many millions or more. The difference between this casket and the previous one is that you will have higher chances of obtaining Gilded drops, and a lesser chance to find Third Age items.
There are less frequent drops that have a low value overall and more that have 1-10 million value like Fury Ornament Kit, Saradomin Ornament Kit, Ranger Chaps, Ranger Gloves, Sagacious Spectacles Fremennik Kilt Black Tuxedo Jacket, White Tuxedo Jacket or Dark Trousers.
Not to be left out We have the most impressive potential Reward Casket that you can find from the Clue Scroll. In this one, even out of the regular drop table, players can be rewarded with a variety of expensive items. Since the caskets of this level has around one million in rewards value it is expected to see items that are in the 100k gold in a lot of cases.
The amount of cheap equipment is not as extensive, so generally, you are able to make an impressive revenue from Master Caskets. It is possible for buy OSRS GP players to also earn unique and mega-rare drops just as in previous instances.