Prior to the introduction of the Metal Zero, the Freehand Mg was the first official Freehand yo-yo made of metal, however its very high pricing was prohibitive to the average player. Several machinists and modders had attempted to create an aluminum yo-yo in the classic Freehand shape. Most notably, Kyo released a small run of aluminum Freehands at the 2005 World Yo-Yo Contest. Later on, a second run of this metal Freehand was released at Infinite Illusions as the Immortalis 2. Along with that, yo-yos such as the Anti-Yo Fluchs and Eetsit, as well as Matt Schmidt's Underdog, were heavily influenced by the organic Freehand shape.
The official Metal Zero debuted during the 2006 Worlds in prototype form at the Duncan table, followed by a wider retail release in December 2006. The Metal Zero sold for around $40 USD, an unprecedented budget price for an all-metal yo-yo at the time. Duncan lowered the price tag by outsourcing production to China, excluding a fancy finish, using lower grade aluminum, and increasing production supply. The original run of the Metal Zero was released in three colors: black, blue, and pink. It is worth noting that the pink was intended to be red, however the manufacturer made a mistake and pink was the result. Rather than anodizing the metal and laser engraving the logo, the colored metal was achieved with paint, which scraped off easily.
The yo-yo has an A-sized bearing, and features a thumb grind lip and a brushed finish. It also has an adjustable string gap and flush-mounted Friction Stickers, which made it slightly less responsive than the Freehand Zero. It came packaged with a casino die counterweight, a Monkey Weight, and a character head counterweight for Freehand play. In addition, it also came with a shorter axle and thinner spacers for responsive play.
After the Metal Zero's initial introduction at Worlds, slight changes were made to the design in response to constructive feedback before the wider release. Some complaints were made that the axle stripped easily, and that the yo-yo would occasionally unscrew itself apart while it was spinning. To address these design flaws, Duncan redesigned the axle. Unfortunately, even after its official release, the original Metal Zero still had some flaws, such as a slightly grabby response, the outer rims getting damaged easily, and the weight distribution and overall design aesthetic had left much to be desired. Despite being the official metal version of the Freehand Zero, it was not regarded by many players to be a serious competitive yo-yo on par with the original plastic model.
In an attempt to resolve these problems, Duncan released the second version of the Metal Zero the following year, during the 2007 Worlds. The new Metal Zero was better designed, had better grade aluminum, smaller axle hubs, and was released in green, pink, gray, blue, and a limited edition deep purple. It has recessed Friction Sticker response, and a brushed IRG anodized finish. There are also two pairs of bearing spacers included for different string gap settings. However, the yo-yo still failed to live up to the reputation of the FHZ, and was later replaced by the Metal Drifter, as well as the 2013 Freehand Al.
Due to its affordable cost and overall failure to meet players' expectations, the Metal Zero was commonly subjected to modifications to make it perform and/or look better.
- The Metal Zero, despite being Duncan's second metal yo-yo after the Freehand Mg, was the first yo-yo that they have made out of aluminum.