After which, the seal was so weak that it was weaker than the shaft mechanism

Good seal, snug fit.

It's leak proof, very good seal.

Because this was OXO and because OXO specifically wrote that these stoppers would remain sealed even with the wine bottle lying on its side, I was enthusiastic in my purchase.

Good quality, helps wine last longer, and has a nice tight seal

They get a better seal than traditional stoppers when used on sparkling wines

Super easy to use, tight seal - I turned the bottle upside down as a test and had no problems

but they seem to have a decent seal, I would buy again

Good seal

It's leak proof, very good seal.

If you want ease of use and a leak proof seal look for another choice.

Had to figure out how they worked as they did not come with instructions.