So, I already have one of those big, metal, double-sided bird feeders where there are ports along the two sides and the full-length bars that the birds stand on are (adjustably) spring-loaded, so if anything heavier than a couple of birds lands on the bar it sags and closes off the ports. I also have a sizeable clear-plastic tube feeder (the kind with brass ports in the tube at various heights, and a catch-tray on the bottom. The squirrels love the tube feeder, as do the birds when they can get a beak in, edgewise. The big metal hopper works very well, but is just not as attractive to any of the yard fauna. So, in an effort to provide an experience similar to the tube feeder, but with squirrel-exclusion, I bought this More Birds Sure Fill No Spill gizmo. It works pretty-much as advertised. The spring tension is not adjustable (like on the big metal bin feeder), but the squirrels had no luck with it and lost interest. The problem is that the birds never developed any interest. I sometimes let the big tube feeder go dry, and that does encourage the birds to move to the metal beast and clean that out within a few days (at least during late summer and early fall). But the skinny little More Birds feeder still gets minimal interest. It holds a tiny fraction of the amount that goes into the big tube, and still it takes a couple of weeks for the level to get near the bottom. The squirrels and birds take the big tube feeder down to completely empty in a couple of days. If that's left empty, they'll empty the big metal bin feeder in about 3 days, and that's virtually all birds accessing that one. The only red squirrel that ever figured out the metal feeder seems to have died or left, and the blacks and greys just never caught on. I can't be bothered buying one of those spinning, battery-powered, squirrel-tossing feeders. This unfortunately tiny-for-the-price More Birds feeder is the last one I'll get for a while. I'll just put up with the squirrels getting half-or-more of the feed that goes through the big tube feeder, 'cuz it nevertheless supports dozens of LBJs(*), chickadees, cardinals, Jays, grackles, mourning doves, some LBJs with reddish face and chest (don't know what kind), and even the occasional small woodpecker. Our indoor-only kitty just loves watching all that back-yard action. So do I, for that matter. But the More Birds 106IN SureFill No Spill X4 Squirrel-Proof Bird Feeder with Four Feeding Ports - while not an abject failure - was not the rousing bird-buffet success I had hoped for. YMMV