...Check the ends and couplers to make sure they are matched.

Just because they fit together, doesn't mean they match. Most guys just eye-ball them, inside the blister pack, then march over and pay for them. Its very seldom that anyone actually reads the specs.

I know there are at least 2 types, 'cause I bought the wrong ones once. I had just started using air power tools and wasn't real sure of the differences - just like your complaint, I started "bad-mouthing" Sears, Craftsman and chinese workmanship. A friend of mine asked to look at the ends and couplers. After looking them over he explained my problem...being the skeptic that I am, and a "self-proclamed" advanced amature professional - I told him he was full of it. Later that week, after he left my pride was soothed and I could actually think straight. I went back to Sears... Damn, He was right. Sometimes it pays to read the directions.

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..."The truth is that there is nothing noble in being superior to somebody else. The only real nobility is in being superior to your former self...” --Whitney Young