Seed tube feeders can be filled with a variety of seed types such as Sunflower, safflower and specialty seed blends.. Quick-Clean Seed feeders are constructed of heavy-duty zinc die cast components, UV stabilized polycarbonate 2 3/4" diameter tube, and stainless steel hardware. These feeders are made to last and are backed by Aspects’ Lifetime Guarantee. 6 Feeding Ports. 1-3/4 Quart Capacity.