Excellent rails. I bought 6 for a RailCore build. Each one was individually boxed and in plastic bags. There was no nasty, stinky machine oil on these like rails I have used in the past. Right from the packages all 6 moved freely under their own weight. They really don't need to be cleaned. You could oil them and put them right on your machine. I didn't measure deflection but none feel loose at all. I highly recommend these.
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