|A Lo-Pro Edge 7 tremolo on a UV77RE|
The Lo-Pro is a minor redesign of the original Edge tremolo to give it a lower profile (hence the name). On the original Edge the string clamp bolts pass under the fine-tuners, while on the Lo-Pro Edge, they do not. This design change means that the Lo-Pro doesn't protrude as far from the top of the body and thus interferes less with the players picking hand and arm.
When introduced in 1991, the Lo-Pro Edge was fitted on the higher-end tremolo equipped guitars except the RG5xx, RG7xx, JS, and FGM models, which continued to have the original Edge. In 1992, it became the standard tremolo for all high-end models. Starting in 1997 select high-end RG models reverted back to the original Edge.
A version of the Lo-Pro called Lo-Pro Edge 7 for seven-string guitar models (including Steve Vai's signature Universe UV77) was also introduced in 1991.
For 2003, both the original Edge and the Lo-Pro Edge were replaced by the completely new Edge Pro, which has a low profile design reminiscent of the Lo Pro Edge. However, the Lo-Pro Edge returned starting in 2010 and continues to be offered (as of 2017).