Oeneo Reference (formerly Altec) corks are made by fusing the purest part of the cork with synthetic cells. The corks are absolutely symmetrical and perfectly consistent- yet totally natural in appearance. These corks retain all of the properties of natural cork but seal better with no leaking. Proven in 10 years of testing to leave no off-taste or off odors. Fits standard size wine bottle necks. 1 3/4" length. Bag of 30. Exact cork demensions are 23mm diameter by 44mm long. Our favorite cork and our cork of choice for our own wines.