These casters work as advertised although I think 150# per wheel might be a bit risky. 2 screws. Those 3/8" bolts on these 4" casters feel a bit flimsy for a 150# rating. I guess it depends on what you're using them for, but for my (heaviest) smoker, they can be pushed to the limit. Remember, when you place your bench, counter, grill or whatever you put on it, the casters will experience a lot of lateral pressure - the casters rotate in the direction of travel. I use these casters outdoors but if you need casters for indoor use you might want to consider others. The smell of it will blow you away when you open the sealed plastic bag. It smells very strongly of cigarette smoke.