Abstract: Improvements result from using a feed roller always rotating at a constant surface speed to feed mail items successively with gaps between them from a stack to a franking machine without undue variations in the gap lengths when there are variations in the mail item lengths in respective stacks. A cam rocks a cradle about an input roller axis to bring a feed roller against the stack at a frequency to feed the items forward one by one. Gearing between rollers drives a two speed transmission to a cam via one way clutches. For envelopes shorter than a predetermined limit, the higher speed drive operates. When a rear mail guide member engages envelopes longer than the limit, a lever allows a pawl to disengage a wrap spring clutch disabling the higher speed drive and rendering the lower speed drive effective.