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 500. Exact cork dimensions are 23mm diameter by 44mm long. Our favorite cork.