Jim Dunlop Tortex picks come in a variety of gauges. The different thickness of a plectrum suits particular styles of guitar playing. Players normally try different types of picks to find one that suits their own playing style.

The plectrums are made of a special plastic known as Tortex. This material is designed to simulate the effect of tortoiseshell picks. The plastic has a smooth, silky, opaque surface that is surprisingly easy to grip even with sweaty fingers

Guitar picks vary in thickness to accommodate the different playing styles and types of strings. Thinner plectra are more flexible and tend to offer a wider range of sounds, from soft to loud, and produce a "click" that emphasises the attack of the picking. However, some argue that heavier picks produce a brighter tone. Tortex picks are available in the following thicknesses (millimetres): 0.50, 0.60, 0.73, 0.88, 1.00 and 1.14.