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enter image description here

My suggestion was that they are for Tamper-evident band, but there isn't one beneath the cap.enter image description here

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  • $\begingroup$ There probably was but it fell off... $\endgroup$ – Solar Mike Mar 21 '18 at 14:42
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    $\begingroup$ It could be a product change in which the original had locking detents, but the current design does not. The legacy design doesn't interfere and it was a money saving move to not re-engineer the cap. $\endgroup$ – fred_dot_u Mar 21 '18 at 15:24
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    $\begingroup$ From left field: if there's dirt on the landing, this pattern will sweep it off into the recesses and allow you to fully screw down the cap. $\endgroup$ – Carl Witthoft Mar 21 '18 at 15:39
  • $\begingroup$ It really looks like it has to do something with assembly process, so it wouldn't maybe scroll while landing that top pump in it, but I need to be sure 100%, I need to know man :) . Btw, all the bottles in my bathroom with pump caps on it have this grooves just like this, only some of them have triangular shape, so it looks like it would turn in one direction but not the other, if it makes sense $\endgroup$ – Kolos Mar 22 '18 at 1:55
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    $\begingroup$ It’s how you get the cap out of the mold. It gets unscrewed. $\endgroup$ – Eric S Mar 22 '18 at 2:29
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that part was injection molded in an unscrewing mold which allows fully-formed threads to be molded into a part. Ordinarily, the resulting undercuts would prevent the part from being extracted from the mold but in an unscrewing mold, a motorized shaft inside the mold unscrews the finished part from the mold after the plastic has solidified and the two halves of the mold are being separated. those features in the cap are engagement splines that mate into the rotating shaft that unscrews the finished part out of the threaded half of the mold cavity.

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