Although the first cork stoppers were tapered, the development of corkscrews made tightly fitting cylindrical corks the norm. Modern corks are available in varying lengths, from 25 to as much as 60 mm (1–2.3 in), according to the bottle ageing aspirations, or extravagant exhibitionism, of the wine producer. (gaja of Barbaresco, for example, perhaps the most ambitious cork buyer, personally selects his 60 mm corks from a supplier in Sardinia.) The longer the cork, the longer it is likely to remain an intact and viable stopper (see recorking), although some oenologists argue that longer corks result in lower fill levels, which may prejudice ageing. There is a limit to the length at which cork effectiveness can continue to increase, since most bottle necks allow only 50–55 mm of cork length to make contact with the glass. There is much less variation in diameter, however, with 24 mm being the norm, although corks 21 and 26 mm wide are not unknown, depending on the inside width of the necks of bottles used.