Refill Orientation Mistakes: How To Spot Them In Packaging
Use the intended outer case and refill together. Start with the correct orientation and note where the refill stops, which features locate it, how it locks and how high it sits. Then try the incorrect orientations that a user could reasonably attempt, using normal hand pressure. A useful locating feature prevents the refill from fully seating or locking in the wrong position without the user having to judge a small visual difference.
Look for a false seat
Check whether a reversed or rotated refill can appear flush, let the outer lid close, or make a click without actually engaging. A click can come from a different contact point. Compare seating height, the intended retention check and the removal action in both orientations. If a refill is intentionally symmetric, verify that every allowed orientation functions as intended.
Compare representative versions
Check the intended version and each refill version approved for the case. Tolerance variation can make a mistaken orientation possible on some pairs but not others. Record the case and refill revisions and the first point at which a wrong fit stops. Treat an arrow or instruction as guidance and check physical fit separately.

Packaging sample showroom of SamBound New Material Technology Company Ltd. Company information: sambound.com.
SamBound New Material Technology Company Ltd.