How Material Affects Tone and Feel
Delrin (often marketed under brand names like Tortex) strikes a balance between stiffness and grip. The matte texture keeps the pick from slipping, and the material wears slowly—you'll lose these picks before they wear out. Tonally, Delrin sits in the middle: not too bright, not too warm, with a slight "chirp" that some players love and others EQ out.
Nylon is one of the oldest pick materials. It's lighter and more flexible than Delrin, which translates to a softer attack and warmer tone. Nylon picks are forgiving on aggressive strumming—the flex absorbs some of the impact. The downside? They wear faster and can feel slippery without a textured grip surface.
Flex materials are designed as a blend concept—aiming for a middle ground between Delrin/Tortex and Nylon. You typically get some of the grip and snap of Delrin with a touch more give and warmth. If you're torn between Delrin and Nylon, Flex is a great "best of both" starting point.
Ultem / PEI is often chosen as a modern alternative to tortoiseshell (now banned). It's stiffer than Nylon but has a slick surface that glides off strings. The result is a bright, articulate tone with fast release. Many jazz and fusion players prefer it for clarity and precision.
Celluloid is the original pick material—what guitars picks were made from before modern plastics. It has a warm, vintage tone with a smooth attack. Many players love the classic feel and the wide variety of colors and patterns available. The downside is that celluloid wears faster than Delrin or Ultem, and it's more brittle.
Material preference is personal. If you're unsure, start with Delrin—it's one of the most versatile. If you want a little more give without going fully Nylon, try Flex. Then experiment with Nylon or Celluloid for warmth, or Ultem/PEI for brightness.