Celluloid Material is most popular pick material (The Original OG) Its the most widely used material worldwide for its warm, smooth and comfortable play ability, perfect for acoustic playing and electric.  Great beginners choice, and pro players. You may have heard it called by other names, Tortex, Grippx, and other names,  This material is a stronger harder plastic, its durability and velvety feel give the player a stronger control and better grip.