Cigarette filters are supplied to the infeed portion (1) of a filter tip attachment machine by a unit (2) comprising rollers (11) which divert the filters (3) into an upstream hopper (8), and a channel (9) carrying the filters (3) from the upstream hopper (8) to a downstream hopper (4) where they are released to the infeed portion (1) of the machine. Located between the infeed rollers (11) and the feed channel (9) is a variable volume storage buffer (16) with a movable wall (28) attached to the top branch (23) of a conveyor belt (24); the Belt is driven by a motor (27) interlocked to sensors (31) which monitor and control the level of the mass of filters (3) occupying the upstream hopper (8), so that the size and capacity of the buffer (16) can be adjusted to accommodate fluctuations in the flow of filters through the hopper (8).