I suppose the screw holds the end cap on.
Not really sure I want a warranty replacement as opposed to just sending it back. Getting something like this really leaves a bad taste in my mouth.
Another reviewer had the exact same issue. Either Competitive/BackCountry sent me this guys defective parts or SportCrafter's has a systemic problem.
There is something fundamentally wrong when your rollers arrive and they don't roll. Out of the box the front roller did not roll because the bearing was not completely pressed. On the black cap of the roller you will find a raised bearing. That is supposed to be flush with the black cap. How hard would it be to spin the roller after assembly? I would not suggest this product.
UPDATE: Competitive Cyclist has been great. They sent out a second set of rollers and set-up the return of the afore mentioned rollers. The second set of rollers are not great. One of the bearings is not completely pressed and there are debris in two of the rollers that make noise when spun. These rollers have had good reviews, but I have not had a good experience. I'll be going with another company.
SportCrafters OverDrive Pro Rollers | Competitive Cyclist
-Tim-