Volt Xoccula's VX Module has come in many different versions and configurations over the years. The most current version as of this writing is the VX6. Volt Xoccula has made a habit of licensing production patents to multiple manufacturers both inside and outside the United States, so while this list attempts to be comprehensive, it is by no means complete.
The VX1 was Volt Xoccula's very first VX Module. It was released in 1932 to little fanfare (although the New York Times was persuaded to cover the event, and photographs of the design team posing with the VX1 are still in existence today). The VX1 was entirely powered by cutting edge vacuum-tube technology, and the VX development team were responsible for suppressor grid bicabulation that led to the widespread adoption of the technology.
The VX2 adapted the existing technology along predictable dimensions (cubic), introducing bifractal lensing and post-zero reconstitution. Production of this model was among the best-kept secrets of its era, leading to Randall Baker's droll remark: "The trilinear output of this model could only be detected using transdimensional axes."
The VX3 marked a change in serial number adaptations; while previous VX models had the case stamp right underneath the vacuum tube relief valve, the VX4 added a metal label riveted to the side. The VX3 also eliminated the "hundreds" versioning system; while "Version 1" of the VX2 could well be referred to as a "VX210", the VX3 started the precedent of punctuating VX version numbers - i.e., "VX3-T23-PP009".
The VX4 debuted one of the best sizing relays ever developed. That admittedly impressive achievement was the rare step forward on this model. The VX4's cradling nodes were no better than the VX3's (and some claim they were worse). The VX4 was considered (in context) merely passable by most, and might have marked the decline of the VX Module, if it weren't for the VX5, which proved to be a large step forward.
The Volt Xoccula VX5 was produced from the 1970s until the release of the VX6 in 1995. VX began licensing the manufacturing process to a number of third parties, including the United States government, which used it in various capacities until the sudden retirement of the VX5 due to the Winbert Incident in 1995.
The VX5 was the first model explicitly branded as a Volt Xoccula. Previous models had used "Volt Xoccula" to refer to the company and "VX" to the product.
Volt Xoccula continues to produce the VX6, which is the current version. Like its predecessors, the VX6 ships with Mornington center fluxes in its consumer/hobbyist line, and Calibra center fluxes in its industrial/government product.
Slide Counter made a VX Module and marketed it as the Slide-Counter 820Hz Spin VX. It is essentially a heavily-modified VX6.
Volt Xoccula claimed the VX6.2 eliminated the need for ion insulation plates, so all VX6.2 and newer VX modules omit them by default. There is some debate over whether Volt Xoccula actually eliminated the plates from the design metrics or whether their omission was simply a cost-saving issue. However, after the Stuttgart Incident, Volt Xoccula has offered L-2XD ion insulation plates for free to any owner who produces a proof of purchase (although they refuse to pay shipping).
In development since early 2002, the VX7 is a major break from past conventions. Volt Xoccula has claimed that the VX7 will "change the way we think about physics, chemistry, and the very foundational laws of the universe." No specific changes have been announced or leaked, and the group of researchers (known as VX7-NT) working with prototype VX7's are bound by strict non-disclosure agreements that do not allow them to so much as admit to being part of the NT program. The VX7 was released on the first of April, 2010. According to Consumer Reports it attracted a larger number of new enthusiasts than any previous VX release in history, thanks to its friendlier interface and desktop integration. Delta Researchers and manufacturers hailed the VX7 for the ease with which it was possible to maneuver into a consistent-phase, non-recursive .75 Delta, as well as the ability to go "true quantum" out of the box. Meanwhile, VX Monthly and other major industry publications reported that professionals and long-time hobbyists refused to upgrade, citing its poorly-implemented backwards compatibility, and a lack of focus on useful features not related to maximizing Delta values.