The handrest has two screws on the back which could be adjusted to allow the handrest to lay flush on the guitar just above the tremolo. The hinged unit fastened into the tremolo studs and moved along with the Floyd Rose. The tremolo bar actually goes through a hole in the side.
Mike Atkinson worked for an Ibanez Dealer when the original Jem was issued and is also the owner of Green Jem #194. He writes:
"The handrest was submitted to the U.S. patent office by Kahler three weeks prior to Ibanez submitting a patent request. The original idea of a handrest seems to belong to Steve Vai, but no one is quite certain. Steve Vai did request the item for the Jem guitars.
"Ibanez licensed the Floyd Rose patent for the whammy bar. Kahler, trying to hold on to 'market share', and holding the patent on the device, would not license the idea to Ibanez.
"Here is an interesting side note. Ibanez did build a number of hand rests. [ed: these were subsequently removed from the guitars and placed in boxes as the guitars arrived from Japan.] Some Jem guitars were shipped with the Handrest while the patent office was reviewing requests. The patent laws restricted Ibanez from installing the device on newly manufactured guitars and selling it as an aftermarket item although guitars shipped with the device during the dispute period did not need to be recalled.
"Ibanez had a number of 'built' Handrests that it could not sell or install on new guitars. There was, however, no restriction against providing the items already built as a gift. Several customers that purchased Jems from me just mailed a letter to Ibanez requesting the handrest with their warranty registration card. A week or two later, the handrest would arrive in the mail.
"Quite a few of the Jem 7's and Yellow and Pink Jems in Western Mass are equipped with the Handrests. I was quite surprised that not all dealers passed this information on to their customers"