The QiYi's WuJi 7x7 adds to MoFangGe's impressive line up of big cubes. At 69.5mm this cube is a similar size to most modern 7x7s. However, it is quite light, weighing only 206 grams. This design features a single-piece construction style, capped design as well as enlarged internal pieces to enhance stability.
If you are serious about 7x7, this is the puzzle for you.