 This feature was offered on models produced prior to the "tailless" period in 1973.Some later models came with an unusual silver grillcloth with sparkling orange threads ("orange sparkle"); a black grillcloth was even fitted on some production runs.During the silverface period, the Twin Reverb's chassis and AA769 circuit was shared by the Dual Showman Reverb, effectively producing the Twin Reverb in a head form, although the matching speaker cabinet for the Dual Showman Reverb sported a pair of 15-inch JBL speakers rather than 12-inch.