Here is another off topic about Hanna that disappointed me. I ordered 4 new vials Thay didn't come with the black screw down caps but these plastic inserts. i wasn't sure if this was the new cap. no matter how herd I press this inserts it's still too tall to close the lid on the checker properly.
So if I toss the 3 old etched vials & save the caps I have I'm still one cap short.
I feel they could have supplied the caps also .
They sell the black caps separately. The plastic inserts I believe are only for shipping the empty vials. I think they also sell individual vials with a cap included. My guess is you just bought the vial only 4 pack?