Stanley 5/16-Inch Heavy Duty Staples, 1500 Count

I used these staples to attach baffles in my attic. The staples easily went into the plywood and held the baffles up well. The vast majority went all the way in sitting flush with very few hanging part way out (I imagine that's partly the stapler, partly the staple). If it matters to you the packing does not look like the picture. I received a flat cardboard box, slide the sleeve out and open one end to access the staples.

Excellent quality, consistency and symmetry, these staples feed and eject superbly. While I don't recommend it, you can even feed them into a decent quality staple gun one at a time and they don't bind or stutter. I have tried many brands of staples and these are among the top 2 (with Arrow being excellent too in my experience).