This product is a set of four vintage 1974 Stackpole 500k potentiometers with solid shafts, These potentiometers are used for controlling various functions on guitars and basses, such as volume, tone, or pickup selection. With a solid shaft design, they offer durability and stability for long-lasting performance. Guitarists and bassists looking to replace or upgrade their potentiometers with high-quality, vintage components may find this product to be a suitable choice for their musical instruments.